The game uses Unity3D, it might only be a matter of ... recompilation :D
The game uses Unity3D, it might only be a matter of ... recompilation :D
It's not. It's a matter of porting, QAing, and then indefinitely supporting a platform that will not bring enough revenue even to cover the developer's time.
It must be nigh on impossible; beyond developer time, support requests will be a complete nightmare.
From what you wrote it should be next to impossible to find them.
Aside from that, games like Factorio, Minecraft, Civilization 6, XCOM2, Shadow of Mordor, Deus Ex: Mankind Divided run on Linux just fine.
Gold or better generally just work. The current ratings for the top 1000 games:
Top Thousand Unrated:61 Borked:6% Bronze+:64% Silver+:59% Gold+:49% Platinum:19% Native:25%
And yet, GNU/Linux is supported by many commercial games: Amnesia, SOMA, SpaceChems, Towerfall, Braid, HyperLight Drifter, Shovel Knight, Undertale, VVVVVV, Hollow Knight, Overload, WarGame Red Dragon ...
So there must be something else there than extra revenue.