I do not have a solution. i can only tell you what happened to me
i have Office 2019 Pro installed in windows 10 64 bit.
after having office 10, 12, 16, etc. so i have created rules for a long time


i needed a new email address so i chose Outllook.com
after this it defaulted to the exchange server, i configured it to be a POP mail.


at this point i did not pay attention to my rules missing.
but now they are.


right now i am reading a "fix"
Redirecting


i tried this , but ti did not repair anything.
so it seems i have another "project"


i can only empathasize