We have new logic dueing repo indexing which looks for orphaned content units after sync and tries to delete them. However, this introduces a lot of slowness in syncs in env with a large number of content units.

https://community.theforeman.org/t/katello-4-9-is-very-slow/34038/9

We need to optimize this operation:
https://github.com/Katello/katello/blob/f9bf7d0065c55e202275de84b9c69b5ebbca9ed0/app/models/katello/repository.rb#L938

and possibly scope it by repo being synced or call this as an async task in finalize to not impact sync performance.

Please clone and make sure we have this flow downstream.