They are certainly not using mmWave 5G. Numbers show (1st Google result) that less than 1% of time connected is to a mmWave network. I don't personally get why mmWave part of 5G is talked so much about.

5G over the same cmWave frequencies 4G uses still has a benefit - but mainly for the operator! It allows them more users and throughput for the same amount of spectrum. So in a rational market, the operators should be giving you discounts for using 5G instead of charging more for it!