I have been playing league on Linux for a while now. I used arch and nixos for a long time with nvidia gtx 1070 and an intel igpu cards. I would say things just work and I dont see any performance issues. There are rarely (once in a year or so) issues when there is a big League update but most of the time it just works. I install league over Lutris
Farewell League of Linux </3
# ❌ Vanguard anticheat is coming to League of Legends, the era of League of Linux is over. * Riot announcement video \(Vanguard @ 12:12\) * Farewell r/leagueoflinux: Vanguard is coming to League of Legends, likely ending the era of League of Linux * Collection of Rioter comments * DotA2 Steam page
in short: ingame: flawless , client: decent, but not perfect
I've been very actively playing on linux for over 3-4 years on opensuse tw and nvidia drivers with lutris installation. I had no issues ingame that were linux only, aside from recently seeing the taskbar at the start of a game sometimes and having to switch to fullscreen and back to borderless, after lutris-lol-ge update some weeks ago. And I remember at the day of first installation years ago some input loss, caused by some missconfigurated stuff which I could fix, but nowadays it installs and runs without any noticable flaws ingame.
The client nowadays works decent but not perfect, slight delays on UI button inputs (noticable in champselect, take an extra second to make sure before locking in), dodging games is pretty much a gamble it only works sometimes (closing every process doesn't help), hextech crafting is slow/delayed. After a game, the client sometimes hangs just like on windows and needs a restart.