ProtonDB says it's decent, the game is Steamdeck verified plus you can return it with under two hours playtime, so I'd just buy it.
Any upgrade path with a pirated version should be completely irrelevant.

Steam has a 2 week refund policy, as long as you've played for less than 2 hours of game time. Buy it and try it, if unhappy refund it

Thanks! I thought it was weird to get that message on this thread.

It's not about being helpful in the sense of just answering the question at hand. If OP just wanted the question answered they can just Google it. Instead I wanted to offer an alternative, low risk solution.
While Ubisoft, EA and consorts can easily stomach some piracy and still crank out "AAA" titles in a 6-months interval, it hurts small studios relatively more. Buying and returning, on the other hand, offers a way to give feedback to the studio via the return reason and costs just as little as piracy.