So i actually tried and timed my steam startup in CachyOS, it's about 5.9sec. Wanna know how Epic Launcher stack up? 2.9sec. Am kinda surprised at how fast it start up, but then i play around a bit and realise it's still as barebone as the old launcher, of course it's able to launch that fast. The real challenge they now have to face is to add features into the launcher and have it still launch as fast.

As for whether the game able to launch or not, i've yet to try, but i assume they'll just use Proton as their compatibility layer.