https://www.youtube.com/watch?v=oItwDXraK1M best quickstart, explains how DHCP and subnets become a thing of the past and how you can basically transfer network hardware between “master” networks without having to touch a host or waste time on routing ports & co. , the main reason ipv6 is so confusing is because the engineers went overkill on the futureproofing after suffering ages of ipv4 being a combination of “temporary” solutions and outdated networking philosophies, it’s a case of “never again”.

This will fuck your plans but you should look at internal ipv6 routing, it’s confusing at first but for situations exactly like this it’s a gamechanger.

That’s the whole point and draw of something like docker-compose lmao - it is that simple.