Astral Chain's got a quirky but lovable combat. I mighty revisit it someday. Fire Emblem Three Houses might be my personal recommendation, though, since it's the only Switch exclusive I adore to death and I have invested hundreds of hours in it. Don't expect too much from the narrative, but the characters are sufficiently fleshed out and their progression in-game is very addicting. Luigi's Mansion 3 is great, by the way, but it wasn't my jam.
My bet with The_Liquid_Laser: I think the Switch won't surpass the PS2 as the best selling system of all time. If it does, I'll play a game of a list that The_Liquid_Laser will provide, I will have to play it for 50 hours or complete it, whatever comes first.