This is the best Pokemon game in terms of pure vibes. There's so much charm and so much to do outside of playing the main campaign. You can walk around with your Pokemon, play minigames at the Pokeathelon, compete in bug catching contests, explore an entire second region after completing the game, the Battle Frontier, the best Safari Zone the series ever had and a really cool final boss, just so many things to mess around with.
The main campaign is honestly the weakest part. It's pretty fun for a big, but a massive middle chunk of the game has every Pokemon around the same levels for hours and hours. Leveling up is a massive pain because there's nothing high enough level to get EXP from, and the game gets extremely dull fighting the same easy enemies for most of the main game.
Thankfully, all of the side stuff is super memorable and charming, and that's the stuff that really stuck with me. This game's at its best when you're just vibing and exploring Johto and Kanto with your team. Awful leveling, but enough atmosphere and detours to keep me coming back.