i don’t like dual booting, i like having all my computing needs in my one linux install, i also don’t use any proprietary software except unfortunately video games, i thought about using VMs but its resource intensive, and read online that anticheats make online games impossible.
Forget gaming inside a VM.
If you really want to isolate it a bit more, how about creating a new user on your system. Do not give them sudo privileges and then install Steam inside the userspace via flatpak (flatpak install --user steam).
That should split it a bit up.
I’ve tried gaming in a VM and while it was great that I was able to do it with a second GPU, it wasn’t worth the headache compared to simply installing another OS. The second GPU also stopped working unfortunately.
Using Steam in Flatpak goes a long way, in conjunction with Flatseal you can limit what kind of access your Steam games have to your files
Online gaming on Linux is nonexistent in competitive games due to you being placed into low trust lobbies. You’d have spend a huge amount of time learning Wine, Proton and linux kernel internals and you’d have to maintain your own sandbox just to separate the games properly.