I have an Optiplex with an i7-2600 and 1050 Ti in the basement. We use it to Parsec games onto my wife's laptop when she (rarely) gets the itch to join in with our boys playing games.

Was the 9700K -> 7700X upgrade a nice jump? I've been running MSI afterburner and keeping an eye on GPU usage and am often only using ~80% while well under my monitor's FPS limit. It doesn't show any CPU cores pegged but I assume that's my bottleneck.