I don't think you'll have problem playing SXSG with it.
I used to have many problems playing Steam games with my Saturn pad-like controller so that's why I always prefer console gaming.
But now I played PC games on my Steam Deck so as long as they are Steam Deck verified, I won't likely find any problems.
Before I got my Saturn controller and was reliant on my XBox 360 controller, I wanted to collect some screenshots from Sonic Generations but the game refused to run. Every time I booted it up, I got a message saying:
"The detected configuration does not match your current hardware. Please re-run the configuration tool."
I already configured the controller and again afterwards but the problem persisted.
That was when I decided to commit to buying a new controller. Especially given I was tired of the drifty right stick.
I haven't tested Sonic Generations with the new controller yet.