No, my question was clear from the beginning:
“is there a way to transfer user-Data from one storage path to another via OCC command.”
you did refer to cp & ln -sf on user base, right, left out all the stuff with the database … I was referring - in general - to the “cp & ln -s” commands in relation to data migrations.
I think the Nextcloud Admin context clearly shows that there is also a database reference, because each file has to be referenced via database with the storage path.
I had once done exactly that many years ago after a hardware change (for testing purposes) - only changed the data directory in config.php and saw that the gui could no longer access various files because the database had referenced a different path.
have a look to this threat (and they are many of them) →
HowTo: Change / Move data directory after installation - 
How to - Nextcloud community
Again my question was really ONLY related to OCC → can i move the same user to another storage path.
sudo -u www-data php occ files:transfer-ownership --path=“path_to_dir”
Normally this command is intended using for two different users … i was just wondering, if this works with the same user …
but it may also be that my question is too hypotethical … I will test it out
$ ./occ files:transfer-ownership user1 user2
Analysing files of user1 …
5179 [============================]
Collecting all share information for files and folder of user1 …
3 [============================]
Transferring files to user2/files/transferred from user1 on 2018-07-09 15-38-56 …
Restoring shares …
Share with id 198 points at deleted file, skipping
1/3 [=========>------------------] 33%Share with id 316 points at deleted file, skipping
2/3 [==================>---------] 66%Share with id 317 points at deleted file, skipping
3/3 [============================] 100%
$