I have the same problem.
I have a home computer running my personal MS365 account. It is also linked to my business onedrive (which I am paying for) and my wifes (which she is paying for). The account shown in each program is my personal one.
I cannot search my work email in outlook only my one personal account (that is rubbish) and in powerpoint, the copilot pro icon would not show up, then I found I must update license (which I did, to the same license). Then it showed up and I found it would not work on a file that I made on my personal outlook but saved to a work onedrive.
I think MS have locked it down to within an inch of its life.
MS did not lock down taking the extra subscription fee though.