With the exception of a handful of titles, this is a quickly evaporating problem, due to Valve pouring millions of dollars into the development of the Steam Deck (motivated by wanting to separate themselves from being dependent on their computer Xbox/Microsoft).
Valve recently passed 11,000 playable or verified titles for the Deck, and since the Deck is Linux, that means 11,000 playable games in Linux (with priority on the most played games)