I am super impressed with Arch on my home servers. People seem to think “rolling” means “unstable” but the only issues I’ve had were due to some weird hardware incompatibility with my motherboard. Once I replaced the mobo my system has been rock solid AND reasonably up-to-date (I do use LTS kernel).
Sunshine/Moonlight should perform better than Gamestream at the default settings.Try turning down your bitrate. 4K will work fine at 100Mbps.