Asus Zenphone 8 problems on Tmobile?

I purchased four Asus Zenphone 8 phones this last Christmas.  The compatibility checker shows they are fully compatible with the Tmobile network, but my family has nonstop dropped calls in the three different metro areas where we spend most of our time (Denver, Fort Collins, Cheyenne).  Additionally, the receiving phone will often not ring, especially when at home, and even when there is plenty of signal.  I am at a loss and very close to quitting my nine year relationship with Tmobile.