AT&T 5G uses Symmetric NAT. It's not rare if you have an iPhone or iPad with cellular. No way to do P2P without relaying traffic unless you want to "guess" the randomized port number, and, on that front, there are NAT-device-aware algorithms that can make that process faster.
We were promised IPv6 will make NAT's not necessary but I believe service providers use NATs not simply to conserve the IPv4 space but to actively discourage using the service to host your own servers.
They are zealously pushing the "ever increasing speeds" of questionable benefit for the user - what for? So that commuters could watch 8k 120fps video while on a bus? Or rather to gather all kind of sensor data in real-time, audio and video included, from their human oil wells? To strip off people's clothes with millimetre wave imaging?
But making it easy for people to run their own home/mobile servers, share and cooperate without govporate oversight is clearly not on their agenda.
We are going backward. Newer 5G and fiber deployments where I live offer only IPv4 with carrier grade NAT. No IPv6, and no real IP unless you ask for one. (Not sure how long they will offer that to non-business subscribers.)
AT&T 5G uses Symmetric NAT. It's not rare if you have an iPhone or iPad with cellular. No way to do P2P without relaying traffic unless you want to "guess" the randomized port number, and, on that front, there are NAT-device-aware algorithms that can make that process faster.
We were promised IPv6 will make NAT's not necessary but I believe service providers use NATs not simply to conserve the IPv4 space but to actively discourage using the service to host your own servers.