MusicBee has a duplicates manager readily available: Tools > Manage Duplicates
(a forum search would have brought that up very quickly)
An alternative method is here:
https://getmusicbee.com/forum/index.php?topic=38885.0You should use the 'regular' version at the bottom.
But it requires setting up a virtual tag, and a library filter.
Both are pretty essential MusicBee features, and a forum search on them will also present lots of information on how to use those.
Best use google for searches: 'site:getmusicbee.com/forum/ search terms'
(the internal forum search is not the greatest)