One advantage of owning a Steam Deck is that you get access to games that the Switch doesn’t have, along with the fact that it’s more of a PC, where you can add emulators, third party launchers and Windows on it if you want. Also, you can stream your games over from another PC, PS5 or Xbox using the many programs that are available on the Steam Deck while the Switch doesn’t even do this at all.
Another advantage of the Steam Deck is that you can find a lot of cheap and good games on sale almost weekly from Steam and other legit keyshops. On the Switch, you have to pay the full price for indie games and ports of games like Batman Arkham Trilogy that play and look terrible while on Steam, you can get those same games for way less than that while having it play and look great as a bonus. Overall, it’s more versatile than a Switch without dealing with some of the nonsense that Nintendo is known to do with their games and online practices.
Of course, if you like playing first party Nintendo games, then you should stick with the Switch since the emulators are a hit or miss when it comes to emulating Switch first party games on the Steam Deck.
Now, for which model to choose from, I’d say go with the OLED if you can get it but if not, the LCD should serve you well.
Luckily, not everyone is buying AAA games on release day and waiting for discounts instead. That’s the rule I usually follow for the AAA games I buy because that’s been the trend for some time now, where it goes full price and then, it’ll get cheaper months later.
I still own a PS5 and Steam Deck and don’t see any reason not to have both since not every AAA game on Steam Deck runs great because there are compromises in performance or graphics while at the same time, the PS5 would run those same games better. Also, you could remote play from the PS5 to Steam Deck if you wanted to, which makes it nice to have both.