Been using a combination of TrueNAS and Debian+ZFS for a long time providing backup services for both production and non-production (personal) systems. As mentioned above, I am using TrueNAS v13 as a Time Machine repository server for 3 Mac laptops at home.

Are you using WiFi or wired network connectivity using OMV?

Feel to reach out via email if you need help (see my profile...).