I've tried to solve this problem here before, unforunately without success but I think I have a potential way ahead and would appreciate some help on putting it together.
The root of the problem is that I have a Microsoft 365 monthly subscription that is not being used anywhere near to its full extent and so in these cost conscious times, I want to get rid of it.
The only thing I really want to keep is my emails (past and future), which pass through my own domain name.
It was suggested here that I could switch to Thunderbird, which I installed but unfortunately, I discovered that my emails are managed by the Microsoft 365 Office Exchange, which doesn't support open protocols and so Thunderbird can't access my emails. It is possible with an add on called owl but this is also a subscription service and I don't know if the emails will still be in the Microsoft system if I terminate the 365 subscription.
Consequently, I think the thing to do is switch my protocol to either IMAP or POP3.
Does anyone here know if this is possible and, if so, is it difficult? Would I be able to import all of my past emails into the new protocol?