Well, I'm not sure I fully understood the bit about macvlan and how you don't need masquerade or use a static route. But I've created a docker macvlan on my OMV box and must missed something and made errors as I cant get a functioning pihole container. It appears to be running but cannot be accessed via the ip I gave it. I'll post a docker question elsewhere as this is now a general question about using docker containers.
Did you end up figuring this one out?
If so could you outline the steps please?