I'm not saying PCs are invincible to malware, but use your own PC wisely and you'll never run into any problems with virus/malware/ransomware etc. WannaCry was as effective as it was because many of the computers it affected were using outdated versions of Windows. Sure, Windows may not be the best choice for large corporations or hospitals, but as long as you actually bother to install security updates, your own PC will probably never run into something like WannaCry. Additionally, OS X/MacOS has its share of vulnerabilities, and if my mind is correct, there's been ransomware that's targeted Macs as well, there's a lot less risk on Macs, that's true, but you can't just safely go around clicking on every ad you see either.
Just a sidenote, I'm not trying to convert you to the "PCMR" or force you to say that PCs are way superior over Macs, just trying to point out that switching to a PC to play WoWS isn't as slimy of a proposition as you think.