I think I found the solution, but not sure if it works in all of your scenario.
So after installed OMV5 with OMV extras, install Docker; Portainer; Cockpit.
Next I've added HassOS KVM VM in Cockpit as a new VM.
Next in OMV5 WebUI go to Network settings and fisrt delete my Interface : enp4s0
After I added a new Bridge, with name: Bridge, and attached the enp4s0 interface to bridge.
Next I set the same static IP address, as it had before with the normal interface. Till that point I didn't Save the OMV5 config chages!!!
After Save to full configuration changes in OMV5, so you will lose the connection only for 2-5 pings.
Finally I've set the existing HassOS VM the following in Network settings: Direct connection; Model type: e1000; br0
In the end of the story, I get a valid LAN DHCP IP address to my HassOS VM, and reachable by local clients.