Maybe you are unaware or treated better than I was. I left T-Mobile when I discovered their definition of 'unlimited' meant that after using 10GB, your connection becomes throttled to around 250kbps for the rest of the month.
No, they have a genuine unlimited plan (for on-device data) these days. The only exception is if you are connected to a congested tower and have used more than 21 GBs your traffic will be de-prioritized (which in practice means under 100 kbps throughput).