Long HDMI cable isn't an option for me. You really dont have a lot of options to tinker with as the default ones are ok. just make sure you get the bitrate on what works and the resolution as well. Yesterday I was able to get an hour session and it was pretty good with no lag.
Also, I moved from sunshine to Vibepollo (fork of sunshine), works as a virtual display so when you connect the monitor where your PC is goes to sleep and has other small improvements.
It helped me to connect the PC (host) wired as it got rid of the minimal lag I had.
Also, I intalled moonlight on my smart TV in the other room and works just as well. So now I have access to it in all 3 rooms. Let me know if it works for you.
Was the only reason to own a console, its exclusives? Even though I'm not interested in PS or Xbox exclusives I can see from a business standpoint how the decision hurt xbox. However, as a consumer, one of the things I really like about xbox ecosystem is having access to games in different platforms. I will always go for a Play Anywhere title when I can as it gives me dual ownership in both PC and console. I hope they can still provide this and the xcloud versions of games that you can play without having to be sitting with your console on.