My friends are understanding that I don't play games with rootkit anti cheat (whether on Linux or Windows). There are enough games that we can play other games together still, and when they want to play the games with such anti-cheat (e.g. Helldivers 2) they simply play without me. No big deal.

Personally I'd be interested to see what would happen if Sony/MS did what they could to make keyboard/mouse experience as good as possible on their consoles (I'm writing from a position of ignorance on the state of mouse/keys with current consoles) and encouraged developers to offer a choice in inputs, so that the locked-down machines can become the place for highest confidence in no/low cheaters. If other people want to pay through the nose to go beyond what consoles offer on the detail/resolution/framerate trifecta then I'm sure they could do so, but I really don't see how you lock down an open platform. That challenge has been going for decades.

This really depends on the friends you have. I've never encountered this limitation because no one in my friend group plays competitive ranked games. Basically anything with private sessions doesn't require anticheat, so Valheim, RV There Yet, Deep Rock Galactic, etc. all work fine.