8 node syncthing cluster with public IPs (IPv6 only) and with config fully deployed and templated out with ansible is up and running now. All of the external dependencies (global discovery and such) disabled.
Just need to cleanup that mess of a playbook (but I won't be moving stuff into roles this time, that cause way too much overhead last time considering that I wasn't going to resuse it anyway and that rewriting it custom tailored to the use case is literally easier...)