Edit: added some more games that I immediately thought of after posting the comment. :D
I would definitely recommend:
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The Big Con if you're into short puzzle/adventure type games. It's completable in about 5-6 hours and (at least to me) incredibly funny.
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Unpacking if you're interested in unpacking a lot of moving boxes and having a chill gaming experience
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Powerwashing simulator: for maximum satisfying gameplay
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Cassette Beasts for Pokémon-like goodness
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Monster Sanctuary also for Pokemon-like goodness, with a bit more in depth RPG elements
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Monster Train: since you already played Slay the Spire (great game, you may want to try another take on the genre. Monster train is all in all pretty similar, but with enough different mechanics, that it stays fresh. All in all I'd say it's a bit more complicated than StS, but if you're interested, it's got enough content for way too many hours.
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Darkest Dungeon: Hardcore RPG with a unique stress mechanics (both in game, and on you personally). Your characters can die permanently, many battles seem unfair and you always play to survive. But it's so satisfying beating a dungeon, a tough boss or impending insanity. This game made me age up 5 years in 2 quests, would recommend.
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Ghost Song: Kinda old metroid like, but also a bit of dark souls in it (because why not). All in all very interesting and doesn't take too long to complete - won't hold your hand, tough.
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Pentiment: Narrative, choice based mystery in medieval Bavaria, great atmosphere and full of little charming details, if you're interested in the setting. Greatly reccomend playing, took me about 12 hours, I think.
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Turnip Boy commits tax evasion: because it's funny and an easy experience.
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Tinykin: Like the Pikmin games, but smaller, less anxiety-inducing, and more platformer-puzzle oriented.
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Scorn: Do you like body-horror and grotesque looking stuff? This game got you covered. Don't be misled by pictures of the playable characters holding guns: it's a puzzle and walking simulator game first, "shooter" second/last. Great visual experience, tough I had no clue what I was doing the first time around.
2 more known games, but I still want to recommend them, in case you didn't check them out already:
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Psychonauts 2: Obv. A sequel, but you don't need to pay the first one, if you don't want to (it's on the Gamepass, just a bit older). It's an action platformed with whacky graphics and powers
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Hifi Rush: Action-Rythm-Game that got everything. Good soundtrack, good fighting, good characters and humor, it's easy to pick up (you don't even need to hit on the beat to complete the game). And probably more I'm forgetting right now :)
Hope this list can lead you to some good gaming experiences!