App that can view "OUTLOOK ARCHIVE FILE" in DROPBOX - macOS Big Sur

Hi all, I need to move bulky old outlook 365 archives off my MacBook Pro hard drive to DropBox to stay there in Offline mode. 

I'm looking for a response that identifies a way to look for a particular email within an archive without having to import the entire archive file back into the MacBook. These are POP3 and IMAP emails. Not Exchange.

 

(The archives must be retained for 7 years for legal reasons. When an issue arises that dates to say, one of two archives, I want to be able to find which archive contains it. Reimporting that one archive would be bearable.)

 

BTW, I have heard of add-ons that can place individual emails into a Dropbox folder, as you go.  The same way you would move an email to a special folder in Outlook. That would actually be better, because not every email is legally sensitive… (And there can be lots of crap in an archive, right?). I looked but found none.