I disagree and I'm too lazy to explain but in short, it's not about High/Ultra settings, that's just name for the settings. It's about how the games look, play, etc... vs how they perform. And I don’t remember that PC gaming was ever before so bad even when we've got shitty console ports.
I think it's important to realise that Fortnite doesn't run because it's being actively prevented to tun on Linux by Epic, not because it couldn't run. It's not really fault of the Linux.
I'll just leave this video guide here to cure world of this cancer
https://youtu.be/xL23Xvv1Pis