Wireless Joint

The MR5100 is an AT&T branded hog-spot and doesn't have all the T-Mobile bands. n41 is T-Mobile's fastest s 5G, n71 second fastest. The M5 has nether.

5G MiFi M5100 Cat 22
Sub-6GHz 5G: n2, n5, n66
mmWave 5G: n260
4G/LTE: 1, 2, 3, 4, 5, 7, 12, 14, 17, 29, 30, 46, 66
3G: UMTS 850/900/1900/2100 ...

This not something that can be done at a userland level it requires some knowledge of baseband level modification. These type of edits on difficult devices and os's is how I make my living so forgive me for keeping it close for a while I will post my tool publicly after this device is older, I ...