To Thunderbird On Windows 10 Migration

I am now on my Mac Monterey posting this because it is easier to login here than on my Windows 10, where the problem is.  Since that system came with Windows Live Mail, which Microsoft is doing away with, I installed Thunderbird last Friday.  After trying to sync it with my Comcast email, it only imported eleven messages while I know there are many more.  Here on Mac Monterey, Thunderbird has been running with no problems.  Back on Windows 10, that system's Mail does not show functions that other versions of it have on other systems.  The add-on for Thunderbird import/export relies on finding that .eml extension where Mail stores the messages.  In File Explorer does not turn up even when checking the box to show hidden folders.  A Search does not bring that extension up.  I do not want to download any more migration tools.  However, I noticed that some articles do not even mention POP3 as an option for the incoming server, but instruct that we use IMAP.  My Thunderbird on Map uses POP.  Could it be on Windows 10 that I must strictly use IMAP?  For now, I must assume that is the case.  On that new Thunderbird installation, I added that Comcast email address again, this time with IMAP.  It imported 240 messages, the number I have online in my inbox.  So, maybe this Thunderbird version will only accept IMAP for Comcast email migration.