I think the idea of Dragonite being OP has some merit. I wouldnt ban it myself, but the mon is Gouging Lite.
Sure if you look at the standard DD set, it's pretty unassuming and easy to check. But the amount of variations it can perform while still remaining effective is crazy. Tera Blast Flying, Encore, Scale shot + Fire Punch, Facade, weirdo Fire Spin sets, Dragon Tail, even crap like Stone edge. You can basically run whatever set you want on this mon and still remain moderately effective. Tera variation is also much higher on this mon than it seems at first glance - Tera Flying, Fairy, Fire, Normal, Ground, and a few more niche types can all cook while being reasonably effective. This mon picks and chooses what it can beat quite easily.
One could argue that Dragonite is more OP than Moon and I don't think they would be wrong... Tera + Multiscale let's this mon get away with some crazy stuff and it can feel a bit Zamazenta-esque with CB vs a few of the lower end BO teams.
During OLT this year, I saw a lot more Dragonite sweeps than Gouging Fire ones on the few teams I saw it on. I think Mimili ran both and they'd usually sweep with TB fly Dragonite iirc.