I just broke my raspberry-pi out again for winter program learning, and I did see that Python is now up to ver 3.10.0. I tried to read through the whats new and I saw several mentions of old stuff being removed, so I don't know if maybe that is part of the slower time verse C++.
Anyway I continue to appreciate the update post, even if I do not understand much of it, understanding only comes when one tries to learn.
Figuring out "why something is slower" is a tough task. We can make some guesses, but in the end we'll probably just have to do a bunch of experiments to determine the answer.