Inside our office 365 tenant, our employees who work as exchnage admins or sharepoint admins have access to the Office 365 username/password
email@example.com. and when we got our root site collection, the Office 365 admin username is already defined as a site collection admin. so now using the Office 365 admin username, i have remove himself from the site collection admin group and i added my username (i am the sharepoint admin employee):-
so now let say an employee who is not a sharepoint developer/admin such as our exchnage admin employees, login using office 365 admin username to do some work on exchange online, and then they access the root site by mistake/intentionally, they will NOT be able to modify the site setting which might cause the site collection to crash. of course i know that using the Office 365 admin username they can go to SP central admin, then add the office 365 admin back to the site collection admin group... but not all of them will do so unless they intentionally want to access the sharepoint site with admin permission.
so my question is, if removing the office 365 admin username from been inside the root site collection admin group, is valid/supported? or it can cause issues? for example we define our audit reports to trim the report each 90 days as follow:- so will this operation be able to work if the office 365 admin is not inside the site collection group..