I’m not very familiar with a lot of networking concepts myself 😂

I think the goal is to have at least one node that can be reached by all peers unless they’re able to find each other through other means. If all nodes are physically isolated (on different networks) than a bounce server is required for nodes to establish the connection, and yes — all traffic would get routed through that node and possibly increase the latency.

I assume the offices have real (possibly dynamic) IP addresses so could you have one of them host a WireGuard bounce server that has the required 51820 port open from public internet?