If you look at the AUR page, most was sorted out for python3 AUR (en) - howdy
The only one remaining with a python2 dependency is the AUR (en) - pam-python and people are commenting and also offering an alternative to drop the python2 from it, or use the pam-python-git (install that one first) instead and then install howdy …
Howdy Beta has dropped the dependency on pam-python altogether. The next version release should solve all these issues or you can get howdy-beta-git from the AUR.
You have experience on this one?
Do you still need to add the pam-python.so into the pam.d like the manual says or how does manjaro know which authentication method to use?