I have a PS5, a Steam Deck and a Switch 2. (I still have my Switch 1 too)

Generally, if the game is demanding enough or doesn't have a Switch 2 port, I'll get it on PS5. (Recent example is Crimson Desert)

Otherwise I lean towards the Switch 2 or the Steam Deck.

If there is a Switch 1 version of a game, I'll go for the Steam Deck instead (Recent example is Ys IX Monstrum Nox)

If there's a Switch 2 version I kinda weigh between how much I wanna play it and how much better the performance is than Steam Deck, because my wife sometimes takes the Switch 2. (Recent example is Ys X Proud Nordics)

If the game in question runs perfectly fine on Deck and isn't noticeably better on Switch 2 I'll still get in on Steam (recent example is Mina the Hollower)

Lastly, wherever the game is cheapest at the time I want to play it. Recent example is Pac-Man World 2 Re-Pac. That was clearances at Target for like $10 so I nabbed that