If using the T-Mobile network you will not be able to use. DNS-over-HTTPS (DOH), you will be required to use DNS-over-TLS (DOT).
We have been trying to coordinate with the T-Mobile team, but they are unresponsive. They are actively blocking DOH-based services. This effects all our apps. Their block results in your internet being inaccessible when on the cellular network if the app is enabled.
All Free Services have a DOT option, and all paid customers get issued a DOT stamp to use. The Android app also uses DOT by default.
T-Mobile CG-NAT
You might also run into issues using traditional IPv4 configurations with T-Mobile Home Internet because of their network topology. T-Mobile Home Internet uses CGNAT – which means end users share IP addresses.
CGNAT (Carrier-Grade NAT) is a type of network address translation (NAT) typically used by Internet service providers (ISPs). CGNAT allows multiple customers to share a single public IP address. This can help ISPs save money and resources, and it can also help reduce the number of IP addresses that need to be assigned to customers.