Questions, I am running everything for OMV and docker on my raspberry pi. Functionality wise for tailscale does it matter if it is installed right on the pi or ran in a container on a pi
does not matter, same functionality.
So with what I am trying to accomplish, would docker still be a possibility to run, pi-hole, tailscale, freshrss, omv and nas, and still have remote access to everything with my phone, and laptop like I was local while being "secure"?
Can't comment on the combination of Tailscale and Pihole in Docker containers, I have no experience with that, sorry.
However, OMV should run on top of Debian, and not in a container. Did not know that's feasible, unless I misunderstood your setup. You want OMV to control the Docker containers.
I think that setting up Tailscale, Pihole and the other applications as Docker containers under OMV is more flexible and safer than setting them up right in Debian.
If something fails, you just modify or delete the Docker container. Suggest to try it out.
And not trying to confuse things, but in case the setup of Pihole is not successful, and as a backup solution, you may want to check out NextDNS.com for the clients...