This very limitation kept me from upgrading my T-Mobile plan for years. I read about Mint on here the last time a plan-related discussion came up, and I switche

This very limitation kept me from upgrading my T-Mobile plan for years. I read about Mint on here the last time a plan-related discussion came up, and I switched to them because they don't throttle tethered traffic. They're a MVNO on tmo's network so you do risk getting deprioritized during congestion, but so far I've been pretty happy. (I hope this comment doesn't come off as shilling for Mint. I just happened to have the same problem as you and was fairly satisfied with this solution.)