https://lutris.net/ integrates Epic Games, Steam and GOG. And for those fine folks who have a Humble Bundle list of games, it also supports that and I think lists all Flatpak games as well. Butt however, ... its vibe coded nowadays. When I install it, then my PC has a problem with logging out. I have no idea why that is, but I tried this twice now (with weeks apart) and every time Lutris is installed, I can't logout correctly without using some terminal commandlines.

I’d love to be more independant from Steam. ... would be my solution if it integrated Steam in it.

I don't understand this. No shade towards you, I just don't get it. If you want be more independent from Steam, why are you requiring Steam to be integrated? What's the point? I really mean this question, so nothing toxic here in case it comes over like that. If you ever stop using Steam, then you can still install Heroic without using Steam.