As stated in post #2, TMobile's "2G speed" is 3G/4G throttled to 128Kbps.

Tmobile partners with Vodafone in India. Vodafone shut down its 3G network in 2021, and this is probably the source of the OP's problem. 4G is mostly offered on band 40, and sometimes on band 3. There are no bands in common with US TMobile (LTE bands 2/4/5/12/66/71).

So it depends on whether the phone in use (not the SIM) supports the Indian bands actually being used in the area. Newer and more expensive US phones do support a wide range of LTE bands, but not all phones do.