I'm working on a set of guides to cover multiple ways to work around CGNAT that covers multiple use case to allow the Emby admin to pick the solution best for them or try a couple things to see what works best. The guide will cover everything from these two services to creating/hosting your own tunnel in a cheap cloud instance for roughly $5/month. This gives you a public IP address that any client can use. The public IP in the cloud instance then uses a dedicated tunnel to the Emby Server.