I took a look out of curiosity. These are the current top 20 games on SteamCharts.com, excluding a GTA V mod and Wallpaper engine and their ProtonDB rating:
- Counter-Strike 2 [GOLD]
- PUBG: BATTLEGROUNDS [BORKED]
- Dota 2 [GOLD]
- TBH: Task Bar Hero [GOLD]
- Apex Legends™ [SILVER]
- Path of Exile 2 [PLATINUM]
- Bongo Cat [BORKED]
- Rust [SILVER]
- Slay the Spire 2 [PLATINUM]
- Delta Force [BRONZE]
- Don't Starve Together [PLATINUM]
- EA SPORTS FC™ 26 [BORKED]
- Dead by Daylight [GOLD]
- Warframe [GOLD]
- Grand Theft Auto V Legacy [GOLD]
- Stardew Valley [PLATINUM]
- Forza Horizon 6 [GOLD]
- Grand Theft Auto V Enhanced [GOLD]
- Destiny 2 [BORKED]
- Overwatch [PLATINUM]
As you can see, only 4 of these are unplayable ("borked"), and 1 has a "bronze" rating. So the majority of the currently top-played games are playable on Linux.
Though Obviously that doesn't help you, if the game(s) you want to play aren't playable on Linux