I am just waiting for a malware developer or state actor to use this as a way to infect computers with 0-days.
This is a disaster. Why anybody would decide to use Windows for any serious workloads is unfathomable to me.
Office products are mostly cross-platform (outlook, word, excel).
I have been exploring self hosting my email.
Docker mail server for backend. Roundcube for web ui
Still keeping accounts at mainstream providers though as backup, especially for outgoing mail.