Change primary storage to Amazon S3

I must change the primary storage from local to S3. Connecting and any things work, I need a way to sycn existing Data to Users. If I use the S3 the data have this format at the bucket e.g. “oid:uid123” . Mounting via s3fs make no trouble but via the native primary storage in the config.php from nextcloud do this.

Nextcloud version 12

pls help

Even in the current version, it is probably not possible to change this in a running setup: