It is 90% arch, except for the few packages it has in it’s own repository. I have it on two pc’s and I have used arch for years I can not say it’s any different from a stability perspective. I almost never have issues on arch but also I wouldn’t recommend cachyos to anyone who had issues with arch. Couse I definitely had to remove custom packages just to fix dependency issues etc.
I did a few times on bazzite. But it’s now aurora. Haven’t had anything I was missing. Was also exporting a few things from arch in distrobox. Was more of a experiment then a necessity.