It generated the password "5L<LP{o<DTeQ?tB" but couldn't display it because of the < ....

Yes, this is a display problem, it has been fixed now. Maybe the browser has some cache, and the next time you open the browser and refresh it, it will update everything.

I think your concept of password strength is wrong-headed. For example, you consider a 64-character password "medium" if it contains only alphabetic characters and an eight-character password "strong" if it contains all four character classes. It is difficult to give much credit to these ratings.

Thanks, I see the problem you are talking about, maybe this needs some improvement, do you have any suggestions for formulating a rating strategy? But in general, passwords with multiple character types are more secure than single letters, which is related to the probability of all relevant characters.

We consider length rating as an important factor, after all, it is indeed useful, thank you for your suggestion!