Pokemon games have always had more or less the same structure. You moved into a new town/region with your mother. You get a pokemon from the professor. Your rival/friend takes the pokemon with type advantage/disadvantage. You start walking, catch pokemon, battle trainers, reach the next city, fight a gym battle, find ot there's a "team X" who are criminals who want to utilize something to manipulate and control a legendary pokemon to realize their criminal goals (often disguised as doing the world a favor in some way, shape or form), they succeed and get stopped by the pre-teen who casually defeats hordes of mooks, leaders, and in-universe gods, and then carries on to fight the top trainers in the region like it's just another tuesday.

There are some variations to this, such as Gen3 having two teams, or sun/moon where there were no gyms, just juiced up regular pokemon. If you've played one of then, you basically have played them all. The best thing about Pokemon is actually just catching them and battling. The story has been the same, with largely the same characters and tropes.