Ah, I'm not going there yet. OpenWRT is an eventual goal. But right now I'm stuck with devices that do not support it. I'm ok with alternate solutions.
Maybe not a docker solution, but you could throw pfSense into a VM and do all that from there
I use it (as it's intended) as my firewall, but I used to use these as general purpose network security VMs in the past (just because I know the product well)
So for you: no firewall rules, just setup DNS with pfBlocker (for the advert blocking) and setup the VPN as required...
huh. Never thought about public pihole servers. So nice of those folks running them.
I don't understand how you're saying you've stopped self-hosting VPN and are still using tailscale. Are you using their SaaS service? Does that allow you to set your own DNS? Do they have speed limits? Are they zero-logs?
Tailscale uses wireshark, which is peer-to-peer. Their "free" plan allows you to set up a network using their "coordination" server, which simplifies administration of your tailnet.
You control dns, exit nodes, etc, so tailscale isn't involved with the vpn itself, hence no speed limits.
You ultimately determine what tailscale collects as far as client logging.
If you block client logging, Tailscale may not be able to provide technical support.
I imagine the docker image serves to eliminate tailscale from the equation.
ETA: there are quite a few ad-blocking dns servers.
I know some VPN providers have their own DNS service that you can use similar to other filtered public DNS. If you mean an in house DNS/VPN gateway then what you want is probably best served by something like a firewall distro (opnsense/pfsense) to handle both of them.
You might look at gluetun. It lets you configure various VPN services from a docker container. The interesting part is that you can point other docker containers to utilize gluetun for networking. Essentially piping them through the configured VPN.
Not self hosted, but I've been using tailscale with nextdns and it has been very reliable. I got tired of worrying about availability of hosting my own