Moonlight/Sunlight are both really great options. The only problem I’ve encountered with either is that the mouse cursor is encoded into the video stream itself. It adds a little bit of lag when moving the mouse and makes it feel not quite right. Steam doesn’t encode to the stream, so it feels much more responsive. Parsec doesn’t either, but it does not support hardware decoding in Linux so you’re going to be stuck with an added ~10ms decode time.
Valve argued in court that you do not own any title in your library and that they are a subscription based service. That’s not very ethical.