Note, I'm just an average to below average player. I started out playing IJN destroyers (dd) and cruisers(CA) so my playstyle, experience, ideas, and conclusions are representative of that.
If there is confusion about my scenarios or examples, i'll add diagrams maybe.
I think you have it backwards about how submarines are disadvantaged since other ships have to use depth charges to sink it or at least I interpret that you consider it is a disadvantage. The fact that we have to use depth charges to sink a submarine is an advantage to the submarines. Surfaces ships cannot use their other weapon types effectively to sink submarines while being forced to give up other targets when using the depth charges. Remember depth charges do not do damage to any other ship types. And it costs surface ships d time (amongst other things) to try to sink a submarine because submarines have damage reduction/damage immunity from shells and torpedoes as well as damage reduction mechanics against depth charges. You know, the one damage dealing tool that is designed solely for sinking a submarine. You could argue Asashio's deep water torpedoes are similar but you forget that it has a 20 km range and will chunk any battleship or aircraft carrier for decent amount of HP unlike depth charges where they do on average 1k damage regularly which is roughly equivalent to one 203mm shell getting a penetration. And there are ships that do not have depth charges like hybrid ships and Leone.
I might as well mention the fact that a submarine has no gun bloom mechanics since their pings do not make them extra detectable nor do the pings have a long reload for something that can force a Damage Control Party (DCP) consistently (ignoring HE spam). Hydro, for some reason, can spot a ship at 5km, torpedoes at 3km but not a submarine (which is bigger than a torpedo) at 60 metres. Submarines can drop off quite easily when hunted compared to destroyers that must endure radar, hydro, and plane spotting.
The statement about carriers launching fighters to spot ships is a problem everyone faces and is quite similar to the problem of submarine spotting while not justifying submarines being able to do the same to some destroyers and other surface ships. The interaction between carriers and surface ships is already bad, using it to justify submarine to surface ships interactions does not lend credibility to your arguments especially when the submarine class is the only one that can reliably dodge or deny the plane spotting. Main point
I'll address the "Show me how a DD like Fubuki exposes it's exact position to every enemy around it when it fires torpedoes" statement. The answer is no. A torpedo cannot give away the exact/targettable position of the destroyer. However, that doesn't mean the player cannot gain information and deduce the approximate location of the Fubuki.
On basic level, torpedoes give away a dd's position by announcing destroyer's presence or at the very least, announces the presence of a torpedo carrying ship the same way smoke announces that presence of a smoke capable ship. It is is less precise than firing their guns (gun bloom) but it tells the enemy that their ship is/was within the destroyer's torp range (ignoring cases where torpedo range is less than ship concealment). The concepts I'm going to present are typically used to determine who the destroyer is and where they are.
I'll set up an example of a T6 only enemy team that has an Icarus and the Fubuki and no submarine, carrier, or Ise.
First, you have the torpedo spread itself. The number of torps and the speed of them. Fubuki has 3x3 59 knots 10km torpedoes that are spotted at 1.5km (ignoring advance warning such as other ships and hydro). The number of torpedoes detected and speed gives an indication of which destroyer launched them by deduction. If an Icarus launched torps, it would either be a set of 4 or a set of 5 traveling the roughly same speed as Fubuki's torpedoes. By opening up the team composition table (default setting: press the TAB button), you can compare the enemy team's list of possible destroyers (Fubuki or Icarus) and count the torpedoes that were sent your way. If you count that the torpedoes showed up in sets of 3, it is a Fubuki. But let us say you didn't bother counting so now you know at least a torpedo carrying ship launched torpedoes at you. This type of information gathering extends to cap zones, angry smoke clouds, and other things by checking the ship list against visible information.
Next is direction, where did the torpedoes show up near you. The direction of the torpedo launch is linear and if more than one set is launched with a noticeable delay, it is pretty obvious which direction the destroyer was moving at the time of launch. This concept is, pun intended, straight forward. Where they show up relative to your ship will tell you where the torpedoes were launched from. The torpedoes sail left to right perpendicular to your bow, and the last torpedo clips your bow (you are facing south let's say) , you know the enemy ship was moving towards you at the time of launch in a south to north direction and launched the torpedoes from the east.
Lastly, there is the detection of your ship. let us say, you are in a Gnevny with no concealment modifiers and you are detected/spotted without gun bloom being active. At T6, no cruiser (currently as of writing this on April 28, 2022) can outspot a Gnevny. So therefore, it is a destroyer. Let's say you were heading south at the time of the torpedo hit. After the torpedo hit on your bow, you turn right and complete a 180 degree turn (now sailing north) and are still spotted. You at this point, have the enemy ship possibly on your east side and definitely within 7km based on your information. Furthermore, it is definitely a destroyer since you outspot/ would detect a cruiser before you become detected by it.
Now let us say, there is an island ahead. Currently, the ship spotting you is within 7km but could be anywhere within the 7km. You sail to the western edge of the island and you become undetected and as soon as you sail past the island, you become spotted again. That tells you that the destroyer is definitely on the eastern side of you and is within the 7km of the island.There are special cases but i'm ignoring them.
The above answers the how to find the approximate location of the ship spotting you. The rest below is not directly related to answering the statement. For relevancy on the topic of submarines, I'll include a section detailing how a submarine weakens the information gathering of the above.
This section will focus on using the above data and choosing a course of action.
At this point, you can choose to smoke up and try to outrun the destroyer or gamble that you can out-gun the destroyer. However, since you know it could be either a Fubuki or a Icarus, smoking up may not seem to be the best option since Icarus has a hydro of 3km and a smoke firing penalty of 2.4km meaning you could get hydro-ed and gunned down without spotting the Icarus if you stayed in the smoke. Alternatively, they could launch torpedoes into the smoke and flush you out.
Now if you had the HP left to gamble, the smoke option isn't bad. You could lay the smoke as you sail past the island while turning 180 degrees to break line of sight and head in a southern direction so that you can pop up on the southern end of the island you used to break line of sight. This puts you at a slight advantage as the enemy destroyer may close the distance to the smoke to proximity spot you, hydro you, or give chase if they think you ran for it. Submarine section
Detection is a tool to find the enemy and Concealment is to hide from the enemy. Sounds simple. It is simple until submarines and carriers show up. If your ship is detected (not gun bloom detected) as you approach a cap zone in the first 3 minutes, you can assume a cruiser or a destroyer is detecting you. Now you know the enemy ship is within (let's say, you are in a Tone with 8.8 concealment and your concealment covers the cap zone but the capzone is not contested or being capped) 8.8km and not in the capzone. If there are islands within your concealment zone (between your ship and the edge of your concealment), it is possible the enemy ship hid behind the islands and peeked out. Or they just entered your concealment zone. Now throw in Tone's planes that can be used to spot the ship, you can easily narrow down where the enemy ship is by flying your planes near the edge of your ship concealment and using the plane's concealment to narrow down where the ship is and spot it. This is based on every ship having a fixed concealment. Any ship can alter their detection and concealment via islands, smoke, cyclone, snowstorm etc.. but that is either dependent on consumable or map effects. When hunting down a ship, often terrain and detection can used to determine a ship's location. A Kagero hull has maximum concealment of 5.4 km (technically 5.37). If you were to corner a Kagero, you would spotted first since Kagero has the lowest/best concealment but also instantly narrows down the Kagero's position to be within your concealment zone. Say if you were in a Yugumo with 5.5km concealment, there would be 100~metres between your ship and the Kagero. With more detectable/less concealable ships, it pushes the envelope of detection further out but also allows you to rule out certain areas faster. For example, if you were in a Kleber with 7.76 concealment but going a boosted speed of 55.44 knots and your concealment edge covered a small set of islands and you were briefly spotted/detected for 5 seconds. you could guess that the Kagero was near those islands since a Kagero that was in open water would continuously spot the Kleber since the Kleber would be gaining on the Kagero and forcing the Kagero to spot/detect the Kleber.
A submarine can alter their concealment and detection at will by diving. This means they can enter your concealment zone without detecting you and then surface and detect you for the first time inside your concealment zone then dive back down and get closer. However, the surface ship will get the detected/spotted indication when they are spotted which based on experience and common sense, would indicate an enemy ship just entered their concealment zone. A submarine's intermittent spotting can cause the surface ships much confusion since it does not have a fixed concealment that can be used for rule out where the submarine isn't. With homing torpedoes, the direction of the incoming torpedo does not indicate where the submarine launched it from.