Using Classic Outlook on Windows for personal email, calendar, and contact management
There does not appear to be anything that corresponds to a "Toggle Switch". There does not appear to be any way to import the PST file. And, by the way, I was online with Microsoft support chat while Microsoft 365 was downloading, and Chat assured me that it could be done. Good thing I installed Thunderbird before I did Microsoft 365. Thunderbird was easy to set up.