In reality, in and of themselves, IP addresses say nothing about your location.
Hulu Live TV local channels are hit or miss since Hulu Live relies on 3rd party IP based geolocation database services that are typically inaccurate for mobile carriers due to their network infrastructure. For me, YouTube TV was a better choice since it is more flexible in establishing your correct location and thereby your proper local channels. Just because geolocation databases evolved to become the norm, they are not standards.
At the same time for browsers such as Firefox, Chrome and Edge running on WIndows there is an add-on available called LocationGuard which let's you establish your proper location - web sites and content providers that utilize the browser's built-in location API will report/use that location (YTV uses that api in the browsers mentioned). Web sites and content providers that use the often inaccurate IP based geolocation services and databases will frequently be wrong. Como @bocaboy2591 suggests a VPN can also provide some relief.
IMHO, it's unlikely T-Mobile will provide a resolution since it's not really their problem but rather a function of content providers and web developers relying upon IP addresses for a purpose other than they were originally intended; however, it's convenient for those content providers to point the finger at mobile carriers. AT least until Internet Standards organizations address the issue…