Absolutely possible if you keep the network setup simple. However, I run different sets of containers as different users, some of which also use services from the host itself (such as a PostgreSQL instance), and things quickly become more complex in these situations. The examples on the github helped me a lot to realise everything I wanted.

If you want to use caddy as proxy for other containers running as quadlets have a look at this repo: https://github.com/eriksjolund/podman-caddy-socket-activation

It certainly demystified some network shenanigans for me.

I usually tell people running MySQL that they would probably be better off using a NoSQL key-value store, SQLite, or PostgreSQL, in that order. Most people using MySQL don’t actually need an RDBMS. MySQL occupies this weird niche of being optimised for mostly reads, not a lot of concurrency and cosplaying as a proper database while being incompatible with SQL standards.

Pretty sure you can unblock per device in Adguard, so maybe block it first then unblock from the logs for the clients you want to allow?

PostgreSQL shitting itself is generally a hardware problem. I’ve had it “detect” faulty RAM modules in a few cases in the decades I’ve been using it.