First of all, a computer is an appliance. It’s not bought with the notion that it has resale value. So whether it has resale value or not is rather moot.
Next up, if you are looking to buy a computer to play games with, then buy a PC. If you use your computer 98% of the time for other things and only 2% of the time for games, then buy a Mac.
Mac gaming isn’t a thing. It never has been. It likely will never be. Been 20 years now and it’s still not a thing.
Ardenweald and FPS drops are a sign of weak hardware and poor code. You can compensate for some stuff with overpowered architecture, but not everything. Reality is, WoW is not that taxing by today’s gaming standards, so if it’s having hiccups, it says more about the state of the game than anything.
You can always run WoW under bootcamp on your current machine to see how much difference there is running under DirectX versus Metal 2. The graphic drivers are what is different between the two. Since they have a massively larger PC development team than they do Mac (cough shall we say you can count the total of Mac developers on one hand assuming there was an accident involving some fingers), your chances of better play experience goes up on the PC side.
Yes, you could buy a new Mac. That’s throwing more architecture at a problem that is still a coding problem. It should improve… but then since it’s new hardware, which requires Mac developers, for which there are few, your odds of having more problems actually goes up because ARM didn’t exist so long ago.
Hell, you could say WoW is actually performing better on older Macs than newer ones in some instances.
So that’s the real context.
If you’re looking to buy a computer that your could sell again, that’s an entirely different usage than gaming. Gamers replace computers hourly for maximized performance. The resale value of their old system never enters their mind even once.
Which are you, a gamer, a Mac zealot, or someone who likes reselling old Mac hardware to justify buying new Mac hardware?