Recover Mac Mail messages from hotmail lost after 9/16/2024?

I had solved Mail/Hotmail issues before by removing the hotmail account and adding it again. I had recently added hotmail as an Exchange account and then, as Microsoft promised, hotmail stopped working. I should not have deleted the account because now it's no longer possible to add it. Consequently, all mail in the folders is lost. While I can access the inbox via Outlook web, none of my "On my Mac" folders are there. Is there a way to get into those folders short of buying a new Mac using the latest OS? I tried Restore from Time Machine but that didn't allow me access to the folders in Mail b/c there is no account. I have made regular external drive back ups so the data is there - it's just accessing it. I'm using High Sierra on a mid 2012 Macbook Pro. thank you!