At a feature level there are things like descriptors and metaclasses, which are complex and rarely-used.
There's a huge number of obscure magic methods/attributes: __origin__, __orig_bases__, __prepare__, __mro_entries__, etc.
It's full of gotchas: methods are looked up on the instance, except magic methods which are looked up on the class, except except __getattr__ and __dir__ on module types. There are both __getattr__ and __getattribute__ and they do different things. Most `typing.Foo` (and also modern `list[int]`) aren't `isinstance`-able. The use of += with tuples. The lack of any coherent numeric tower. Etc. etc.
I think it's very clear that Python has grown organically, and is now struggling under the weight of all its bolted-on extra bits, or sheer unnecessary complexity. I would love to throw it all out and start again.