Is there a way to monitor the amount of traffic & connections for external clients?

from within netmaker, no. on the ingress gateway itself you can get this infomation from

wg show

Can I also use it if netmaker is running inside a container?

yes, you just have to exec into the container to run

wg show

... eg on netmaker host

docker exec -it netmaker wg show

Oh, alright Thanks 🙂