i have a laptop that can barely run a youtube video, and in order to use my PC to play games around my house I use steam's built in game streaming feature to remotely stream the graphics config menu. i have my wireless keyboard & mouse plugged into my PC, so after i stream the config menu to my laptop i use the keyboard and mouse to minimize it on my PC (not using the laptop's controls) and boom, now what steam thinks is hitman is actually just a remote connection to my PC.
ik there are free programs to do this but tbh theyre more annoying to use than steam's built in feature, and i havent noticed this working worse (may be better, really)