Hello,
I set up Azure AD sync on my O365 about year ago but I created new server using windows server 2019. What I did was start from scratch and moved over users, policy, etc... It has a different domain and netbios name. I wanted to make my O365 a "local" copy again and add the azure ad sync but cant delete the directory from Azure because when i go to delete users it is greyed out.
Not sure what really to do thinking of scrapping O365 as a whole and starting that fresh too...