Can I configure my user home folder (configured in UMC) as “User home folder” for Nextcloud?
Even though it is possible to mount file systems from the docker host to a docker image this has to be configured by the app vendor.
Currently, this feature is not configured so it is not possible to use the UCS home folder as Nextcloud home folder.
Additional Information and Workaround
We have a CoolSolution article which offers to mount the Samba shares as external storage to Nextcloud. But you will have two places then instead of one as desired.