I heard a rumor that some open source World of Warcraft is about to launch and rather sooner than later. If the rumor is true, what is the project name and is it available for Linux?
I've never played the game but I would give it a try if it is released for Linux.
Be sure to note where Lutris is installing your games (it's configurable), so that if you decide to use add-ons you'll know where to put them. I used WowUp, specifically the CurseForge version to manage my add-ons.
WoW itself runs pretty much flawlessly. I may have made some VK3D tweaks, but I'm not home and can't check my notes. Let me know if you run in to any problems.
WoW server emulators have been in development for over a decade, they're public projects on GitHub and released under opensource licenses, all private servers use those emulators, none of them has original code, it's never been stolen.
You can compile them for Linux (as well as Windows), how well they work depends on the version, up to WoTLK they're fine, from Cata on they're quite bad.
You will need the original clients that are Windows only but they work flawlessly with WINE.
If you never played WoW before, I suggest you play the official one before dabbling with emulators/private servers, it's a much better experience if you know nothing about the game.
WoW client is not native on Linux but it runs flawlessly regardless, always have, it's also very easy to install with Lutris: https://lutris.net/games/world-of-warcraft/, use the battle.net script and follow instructions to install dependencies first.