I am behind a Double-NAT. My ISP doesn't give me just 1 IP because it's dynamic. In order to expose my local machine to the internet, I am trying to host wireguard on aws and forward the ports there. Then I would connect my local machine to the wireguard.
I didn't even know this was a thing, but it makes sense. It's like someone setting up another router on your home network and putting you behind that. You can only make outbound connections. I'd prioritise a better ISP but in lieu of that the tunneling back in over the outbound connection makes sense.