Here's an interesting little data point for you, as the developers behind the polar exploration and survival game The Pale Beyond have given an update on Steam Deck engagement with their game.

At launch, Steam Deck players made up 10% of the playerbase for The Pale Beyond. 9 months later after sales/etc that number has dropped to 5%.

Both numbers are significantly more than the steamOS user percentage (0.5%), so we can make the assumption that Steam Deck users make up a disproportionately high amount of games sales, and particularly full price sales for new releases.