Comment by Aachen

When first migrating away from Hotmail as a teenager, I just registered for new accounts/contracts on my own domain and migrated only the stuff I was still actively using

At some point I downloaded the emails from Hotmail by adding the account to Thunderbird and copying the contents to a local folder. Probably imapsync or some other dedicated tool would be more reliable but it seems to have worked for me (don't forget to also copy the sent folder). I don't really look back at it anymore, after a few years nothing of interest lands there. It's still out there though. Data hoarder issues with definitively deleting the data from it

I'd keep the account name just in case someone finds that it can be re-registered and used to gain access via password reset somewhere