A lot of mobile telcos use IPv6, but there are virtually no telcos around the world that don't force the use of some form of NAT (CGNAT, NAT64) for connecting to legacy sites. NAT64 is effectively another form of CGNAT, you only have a proper end to end connection if you're using IPv6 directly.
TMO US has 110 million customers, but they don't have 110 million legacy IP addresses, and most other telcos are in the same boat.
Mea culpa. I'm away right now, but I'm like 95% sure that T-Mobile Home Internet is NATing, or at least was awhile back when I had trouble. Googling around it sounds like it may operate differently than the mobile phones do.
Demonstrably false. T-Mobile US mobile clients are IPv6-only and connect via IPv6 to IPv6 sites:
* https://www.youtube.com/watch?v=d6oBCYHzrTA
* https://www.youtube.com/watch?v=nNMNglk_CvE
NAT is only used to connect to IPv4-only hosts via DNS64 (with or without 464XLAT). As of 2022Q2, T-Mobile US has 110 million customers:
* https://www.statista.com/statistics/219577/total-customers-o...
One-third of the US population is connecting via IPv6-only on a day-to-day, hour-to-hour basis every time their smartphone reaches out over the radio.