

CachyOS is most definitely not “as close as it gets” to SteamOS. Cachy is performance driven whereas SteamOs much like Bazzite is compatibility driven. Valve’s main goal is for their distribution to run on everything, performance is a low priority.
better scheduler
That’s not a thing, the words you’re looking for are “scheduler optimized for gaming at the cost of performance in other domains like power consumption”, you also don’t need it because common programs like gamemode already do this.

CachyOS is not a gaming distro, it is a performance distro, and this is from the mouth of its own developers. Everybody thinks their scheduler is the best - there’s probably a meme about it somewhere, you’d probably get more aggressive scheduling with gamemode than regular cachy because gamemode expects you to be playing a game when you use it… and fyi gamemode is used by default in applications like lutris.
SteamOS is a desktop distribution now, that means full compatibility - at least once they start supporting nvidia. Maybe when they supported only the steam deck they could afford some targeted optimizations, but the more systems start running SteamOS the wider the target will have to become.