Type hints aren’t a single addition - with every release they get more complex. It wouldn’t surprise me if the language included 20+ typing-related PEPs by now.
The other obvious example of complexity is pattern matching. The feature is very complex, especially how it breaks established rules of the language. It also required fundamental changes to the interpreter to accommodate it: a rewrite of the parser from simple LL(1) to PEG.
> It also required fundamental changes to the interpreter to accommodate it: a rewrite of the parser from simple LL(1) to PEG.
The PEP 617[1] (the PEG change) doesn't mention pattern matching at all.
[1] https://peps.python.org/pep-0617
Guido said for many years (decades) that he wanted to get back to the parser.