Hi,
alternatively, you can check out these 2 guides of mine. At least they include the command syntaxes for rsync that I used during my migration.
Here’s a guide for migration via rsync – Migrating Nextcloud AIO Docker Server from ext4 to xfs - #2 by vawaver
Here’s the complete guide for VM in Proxmox, including all possible settings – Proxmox + NGINX + Nextcloud AIO + Watchtower Deployment Guide