I think it's a matter of perspective, which mostly depends on your attitude to AAA online multiplayer. Those represent a huge % of copies sold and hours played for PC gaming (They are certainly the majority of titles on the most sold lists).
Many of those titles also have windows-only anti-cheats (Valve obviously being a driving force for Linux here).
So if you look at "N titles of M work well" then the Linux glass is half full. If you look at "X hours of Y of the total played hours of recent popular AAA games are played on games or modes that work poorly on linux" then it's still half empty.
Unfortunately it's not by hours but peak concurrent players. It's also pretty similar to the top grossing list. I checked each games Steam Deck rating and if it was verified or playable (usually means it needs text entry with a keyboard or doesn't support controllers) marked it as "works" (with the exception of TW: Warhammer III which is listed as not working because the performance isn't good on Steam Deck but it's a native linux title). If it was unsupported and the reason was given I marked as so, if it was some other reason I checked ProtonDB and noted the rating. I assumed if Valve marked it not supported it doesn't work regardless of ProtonDB rating (except again TW:Warhammer III). Out of the 90 titles there 21 are marked unsupported mainly because of anti-cheat or 23%, when weighted by player base that rises to 26%. So arguably it's 3/4 full. ;)
Of course if you demand every title MUST work and no alternatives will ever suffice I doubt you'll ever be satisfied. Anti cheat also gets rarer as you move away from big online games.
Here's the full list:
Over 240,000 Peak players:
Goose Goose Duck - works
Ark Survival Evolved - works
Elden Ring - Works
Dota 2 - Works
COD MWII (2022) - Doesn't work, anticheat
PUBG Battlegrounds - Doesn't work, anticheat
Yu-gi-oh Master Duel - Works
Apex Legends - Works
Lost Ark - Doesn't work, anticheat
CS GO - Works
Destiny II - Doesn't work, anticheat
Dyling Light 2 - Works
Over 130,000 peak players:
Cyberpunk 2077 - Works
New World - Works
Monster Hunter Rise - Works
Total War Warhammer III - Works
WB Multiversus - Works
V Rising - Works
Path of Exile - Works
Team Fortress II - Works
Naraka: Bladepoint - Works
Rust - Doesn't work, anticheat
GTA 5 - Works
Wallpaper Engine - Doesn't work? (is it really a game though?)
Over 75,000 Peak players:
Raft The final chaper - Works
Vampire Survivors - Works
The Sims 4 - Works
Rainbow Six Siege - Doesn't work, anticheat
War Thunder - Works
Fifa 23 - Doesn't work, anticheat
Left 4 Dead 2 - Works
Unturned - Works
Witcher III - works
The Forest - works
Civ 6 - Works
Valheim - Works
Fifa 22 - works
Football Manager 2023 - Works
Dead by Daylight - Doesn't work, anticheat
Dread Hunger - Maybe works? ProtonDB says Gold
Warframe - works
Terraria - works
Football Manager 2022 - works
NFS Heat - Works
Warhammer Darktide - Maybe works? ProtonDB says Gold
Warhammer Vermintide - doesn't work, anticheat
Lego Star Wars Skywalker Saga - Works
Over 40,000 peak players
Skyrim - Works
Euro Truck Simulator 2 - Works
Fall Guys - Doesn't work, anticheat
Don't Starve Together - works
God of War - Works
Gundam Evolution - Doesn't work, anticheat
Cycle Frontier - Doesn't work? ProtonDB gold
Stray - Works
Deep Rock Galactic - Works
Stellaris - Works
The Scroll of Taiwu - Works
Mirror 2 Project X - Doesn't work?, ProtonDB silver
Conan Exiles - Doesn't work, anticheat
NBA 2K22 - Works
Farming Sim 22 - works
Marvel's Spiderman - Works
Battlefield 1 - works
Battlefield V - works
Risk of Rain 2 - works
Crusader Kings III - works
No man's sky - works
Final Fantasy XIV - works
Red Dead Redemption II - works
Warm Snow - works
Mount and Blade II Bannerlord - works
World of Tanks Blitz - Works
Payday 2 - works
Hearts of Iron IV - works
Super People 2 - doesn't work, anticheat
Stardew Valley - works
7 days to die - works
phasmophobia - works
VR chat - doesn't work? ProtonDB gold
Undecember - works
garry's mod - works
Halo Infinite - works
Stumble Guys - works
Day Z - doesn't work? ProtonDB gold
Mir4 - doesn't work? ProtonDB borked
Project Zomboid - Works
Cult of the Lamb - works
Victoria 3 - Works
Rimworld - works
So if you look at "N titles of M work well" then the Linux glass is half full. If you look at "X hours of Y of the total played hours of recent popular AAA games are played on games or modes that work poorly on linux" then it's still half empty.