I'm having this issue but with my iPhone 13 pro Max... Pretty sure it's a T-Mobile issue and not specific to a device Even though I haven't encounter that issue on my Pixel 6 yet
Red Pocket (using the TMobile towers) is my provider and I get pretty good results in the north Dallas area...I do get lag issues at the Cowboy games but not at the Maverick games....probably getting throttled because of the number of users around me??