NetMaker, at least based on the quick install manual, asks you to open up the following:
- 443, 80 (tcp)
- 3479, 8089 (TURN, TURN api)
- 8085 (exporter EE)
- 1883, 8883, 8033, 18083 (if using EMQX)
But perhaps none of these are required for actual WAN/Wireguard connections and one needs only limited access to these ports in order to configure the software.