Installed in the last week. Ran into an issue starting the game on EndeavourOS using Lutris without steam but quickly resolved it by deleting some of the game files so it forced a redownload.
The graphics looked fine to me using the AMD 7900 XTX in all of the menus but when I got into a match most UI elements and cards were blacked out. Switching from "ultra" to any other graphic preset fixed the colors for me.
I haven't tried using Steam or Proton for Arena