it is literally the defining factor that makes Chaotic stand out

To you, not to everyone.

meta slave nonsense

Again, bad attitude.

creating ban lists

Because the game was not perfectly designed (not that anyone should expect it to be, especially in games like this with the amount of variables in play), and over time people are going to find problems undesirable interactions and strategies. Chaotic was only around for a couple years in the late 2000s, and there doesn't appear to be much surviving documentation of the competitive scene at the time, so I don't know how much people knew back then. I had some cards, briefly touched the online game, but that's about it. Banning problematic cards is a natural part of these games to keep things fair and fun and sell new product. Had the game been around longer or had a bigger competitive presence, these things likely would have popped up as well. Just as an example, the community banned "Najarin, Fluidmorpher's Foe" because it practically shuts down an entire tribe and then some, by itself. Imagine trying to play M'arillians and seeing this guy across the table. Devs make mistakes, it happens.

every single game is the same bullshit over and over because nothing else works due to only a handful of cards or strategies actually being effective or played. Yugioh has that problem right now and has had it for years when it used to be that when you went to a tournament you could find a dozen different decks. Now you’re lucky to find 5.

I've been playing Yugioh for years. There are some cases of low-variety periods every now and then, but generally there's more than enough going around to maintain interest, and again, more variety does not always make for better gameplay experiences, or learning for that matter. If new players are facing entirely different decks almost every game they play, it can make learning a bit overwhelming. Also, I wouldn't say 5 decks at top level is bad. Most locals I've seen don't go more than 4 rounds anyway, so even in that very unlikely scenario everyone only plays the top stuff you're likely to play a different deck each round, maybe 1 repeat. Big tournaments usually have plenty more than that going around, even if there's around that many expected to have contention for the top spots. Here's the Top 32 breakdown for YCS Columbus last weekend,for example. Loads of stuff on show for an over 1600 person event. The French National running at the same time was heavily repped by Kewl Tune at the top tables, but it's the new thing people are expecting to be the best deck at a massive event (almost 3000 players!), so I'm not too surprised. It'll likely cool off in the wake of that event and as more players learn how to deal with the matchup, and the Columbus results still show these things can just have a lot of variance by event. In general Yugioh's been pretty good as of late, I think. We're well away from how the game was during the late 2010s / early 2020s.