The game is Stray. Developed by Blue Twelve. Published by Annapurna Interactive.
https://en.wikipedia.org/wiki/Stray_(video_game)
Without spoiling anything, there's way more to this than just a cat simulator. Loving it so far, in any case. I recommend this to anyone who loves exploring new worlds, interacting with lots of locals, solving puzzles. Everything about it has both a familiar RPG feel and also a sense of new to it. And it plays really well on Linux via Steam.
This was the first game I played on my Steam Deck when I got it! Had a tiny bit of trouble with lagging, especially when there were a lot of enemies on screen, but some tweaking in the settings fixed it. Had a lot of fun with this game, though!