I can’t say anything about EAS because I did not test it.
EAS is a protocol designed for mobile, while most desktop clients use the EWS (Exchange Web Service) protocol.
I tested this a lot and tried to reverse engineering the communication of several desktop app to understand what’s going on.
The conclusion: EWS does not work with OAuth for personal Outlook accounts with one exception: Apple Calendar. For some reason they can use it.
Never got an official reply from MS on this matter. My understanding is that EWS is being deprecated and therefore they don’t want vendors to keep using it. Apple probably got a special del to be able to keep using it.