hey there! i know a ton of pokemon, so i can help in any way you need ^^
personally, one of my favorite parts about it is that there is no one way to “correctly” get into pokemon. a lot of people just play certain games, or collect plushies, or trade cards, or watch the show, and they’re all equally fans! plus, there’s a pokemon for everyone, with 1k+ pokemon, you’re probably going to get really attached to a couple on design alone. lmk if you need any other help/questions ^_^

hmm well, the thing about pokemon is that there isnt really one "story", like there are different continuities so it might be a little difficult to explain. most mainline games have their own story to them, sometimes they connect but most of the times they dont. then the sidegames are either completely in a different universe (ie: mystery dungeon or pokepark) or so unconnected it doesnt follow a big story (ie: channel, dash). the closest pokemon has to deep lore is like, myths surrounding legendaries and how the world was created, but even that is a bit contradictory itself. if you want a more historical approach, i guess i would recommend pokemon legends arceus, which is a game that takes place in the past, when a region was founded.
otherwise, different mediums have their own lore! the anime is entirely its own universe, there are many many manga, but most people follow pokemon adventures, which has its own lore too.
sorry dont mean to make it complicated ^^; pokemon is just a very big series lol

I think the easiest way to get into it is to to quote the game professors:

"This world is widely inhabited by creatures known as Pokémon. We humans live alongside Pokémon, at times as friendly playmates, and at times as cooperative workmates. And sometimes, we band together and battle others like us. But despite our closeness, we don't know everything about Pokémon."

Now pokémon usually has one main story per game focusing on a certain legendary trio of pokémon (the ones in the art of the game box) but all these stories happen in the same universe (except for some side games), so i'd recommend focusing on a legendary you like and going from there, while you could use a normal pokémon usually the only lore these ones have are the pokédex entries you get after catching them, more info on them can be found externally like youtube shorts or an episode of the anime.
Usually you get attached to these normal pokémons by something that happens on the game, like it saving you from a loss-