Games up until Platinum and arguably Black/White were actually decent, so that would move the goalpost to early 2010s. Then, it would be an accurate statement and I would agree with you.
Pokemon's battling mechanics are actually a lot more indepth than you would think. That's the beauty of it: A literal child can play and finish the single player portion, but good luck competing in Battle Tower clones or on Showdown without doing your research on every anal and obscure facet of the system and keeping up with how every single pokemon works and evolves by the way of metagame.
High level competitive play is something else, I would argue that you haven't actually played the games at all until you experienced it in some capacity.
I recommend "False Swipe Gaming" and "BKC" channels to get a primer on how more competitive side of the franchise works. If you're actually new to the whole concept, FSG is especially better since he breaks down not just how every pokemon did in every generation but also talks about every generation's specific metagame and what shaped it, why and how that specific pokemon fit(or failed to fit) in it.
BKC is a sperg like me that makes hour + long videos on whatever he feels like it, you need some context for most of his videos that you can get from FSG but he can show you just how indepth the games can get. A far cry from just mindlessly pressing A to get past trainers in single player, which is more or less just the tutorial for the main course in my opinion.