How to migrate local external shares to "native" shares

Hi. We have several local external storage directories which are local files on linux nextcloud installation.
However, we want to make them “normal” nextcloud directories which are stored in NC data directory.
It’s easy to just move the directories within filesystem - so they are in data - but we are not sure how to not make nextcloud clients confused.
For a NC user, they will be removed from access to external directory (or the external directory will just be unmounted) - and then they will get access to the same directories as shares (shared by “Admin” user).
Ideally, NC desktop clients would not remove and re-download the files, but notice that these are in fact same directories. How can we achieve this?