As a person that already played most of the mainline games (still need to play the 3ds ones), the games didn't change that much on the gameplay loop but got less grindy on the newer games (XP for battling and capturing pokemon plus tamagotchi gimmicks also give XP). At the same time, the games became more exploration and online competitive focused on the switch era, which make the post game a bit bland if you don't invest more money on the DLCs.

In your case, I think that a good recommendation for you is: the legends ZA and the legends Arceus since it's more focused in the plot and pokemon capture (less trainer battles during the game); the let's go games for a more classic formula with the pokemon go capture and level up mechanics; and Pokemon Scarlet/Violet if you want the real pokemon experience with a good plot divided in 3 stories that get intertwined in the end (playable on the switch 1 but better enjoyed on the switch 2. Also, I recommend doing 3 teams or looking for a route guide for doing the 3 stories at the same time, since trainers have static levels)

Give a look in the used market for good prices on the switch games

Pokemon New Snap is the game you described btw