You are probably looking for something like games on whales https://games-on-whales.github.io/. If you have an extra weak gpu or an integrated one besides your 9070xt, you can use that for the video transcoding and the big gpu for the game rendering

Besides the time and responsibility of running the service, your biggest cost is going to be storage and maybe even transfer. None of the cheap VPS have big storage or bandwith, so I would not offer a service like this if I were you.