DDNS univention-DHCP update with non-Windows-Clients

In my home network I have a UCS-AD master with a DHCP server (version: 5.0-2).
In addition to some Windows clients as AD domain members, I have various non-Windows hosts that do not belong to AD (Raspberry, Shelly, ESP-Tasmota,…).

The Windows clients belonging to the UCS AD domain update their DNS entry themselves as soon as they have received an IP from DHCP, that’s OK.

What do I have to set up so that a DNS entry with the host name given by DHCP and the assigned IP is also created or updated for the other IP clients?
There is a reservation in the DHCP for each IP client. DHCP is also allowed for unknown clients.
In my attempts, I came across the “DHCP DNS Update” policy in the DHCP management, which I configured for my subnet. No DNS entries are created / updated for the corresponding clients.

Is it all possible as I imagine it? If not, what is the “DHCP DNS update” policy for?

thank you in advance