So Sunshine and Apollo are continuations of Nvidia's EOL'd GameStream tech, which is designed to mirror the local display to a device. It doesn't really have the concept of a "user session", it allows you to mirror the currently running local session remotely.
> If that's the case, it feels like it's just TeamViewer or Remote Assist session where you hop in to an existing session
Yes, it's pretty much that, but optimized for A/V latency and game inputs (games that "trap" the mouse in fullscreen are well supported and controller inputs are passed through).
I haven't really used TeamViewer/Remote Assist heavily, but I wager if you wanted to game with those tools it would be a worse experience than something like Sunshine.
> If that's the case, it feels like it's just TeamViewer or Remote Assist session where you hop in to an existing session
Yes, it's pretty much that, but optimized for A/V latency and game inputs (games that "trap" the mouse in fullscreen are well supported and controller inputs are passed through).
I haven't really used TeamViewer/Remote Assist heavily, but I wager if you wanted to game with those tools it would be a worse experience than something like Sunshine.