2-5 seems super short for anything haha so I am guessing you want to play something where you don't have to think too much. Very chill games where it is easy to just pause and then get back fast to where you left off.

• stardeew valley - you can be super efficient or just super chill about it, the game won't punish you
• I haven't tried bloons td 6 on steam deck because I had finished it before I got my deck (exist as app too) but that would be pretty perfect fit too.
• Cozy grove is exactly maybe 5-15 min per day. It is a bit too slow for my taste because of that. It is a very chill puzzle like game.
• Death doors, very easy to just pause mid game and very nice visual and story. The game is maybe 5 h long if you try to get all of the achievements. But it is a great game none the less
• Moon lighter - rouge like and store management, very chill and all days are pretty much the same so you don't have to be efficient
• monster sanctuary - pokemon but 2d platformer
• Pyre - can pause pretty easy before every challenge. I wouldn't pause mid challenge tho. But you can. Great story and great strategy game
• Ring of pain - rouge like but with cards. Easy to die so one session can be very short if unlucky or maybe that is lucky? 😂
• Spirit farer - great story and can be paused very easily mid game and you can take your time in everything or do it quick and dirty
• Vampire survivors - like others have said
• West of death - rouge like, easy to pause and a pretty brain dead game (not in a bad way)
• the final station - very very easy to jump in and out of. Most station is pretty short so this can be played easily with weeks going by and still just jump in and play. The story is very easy to follow
• katana zero - platformer, very cool and easy to jump in and out of. Short missions so if you don't want a perfect score could you do many bellow 5 min maybe even in 2 min. Pretty short game tho story wise
• legend of keepers - rouge defense. every wave is pretty fast to go through if you have put up your traps and monsters correctly/good enough
• Nitro kid - rouge like but turned based. This one can be both fast and slow depending on your choices