Looking at the GitHub repository, I think the author of the add-on just needs to make one small change to fix the problem mentioned in this error message.
In anki_funcs.py, just change:
from PyQt5.QtWidgets import QMenu
to
from aqt.qt import QMenu
However, there could be other 23.10 compatibility issues besides just this one. This forum thread could be helpful for the author: Porting tips for Anki 23.10
The short-term solution for you would be to use the Qt5 version of Anki 23.10.1 instead of the Qt6 version. But this short-term fix will probably stop working in a month or two.