Epic does have its steamworks alternative called epic online services which provide more or less the same functionality (achievements, p2p networking, anti cheat…) but it’s also completely free, cross store, and cross engine

https://dev.epicgames.com/en-US/services-games

I heard back than that the open source driver is pretty much just a layer of abstraction and that most actual code runs in the firmware which is proprietary

Update : i’ve been trying doom eternal with raytracing for quite some time now and the performance is excelent. It never drops below 144Hz with all settings maxed out at 1080p. I know that doom is really well optimised so don’t take this as a general review.

Valve’s custom wayland compositor used on steam os