VPN (SonicWall) will not connect over T-mobile 5G Hotspot

I have had the same problem with my Samsung A32 5G for the last 3 months, giving up. All devices connected to its Hotspot go to "connected without internet" any time after connection, rendering Hotspot virtually useless. Two more warranty replacement units failed in the same way.  The same A32 of my wife's works fine though, even VPN connection too.  Oneplus N200 5G and older Samsung J7 Star work flawlessly.  5G related? What is going on, T Mobile?  I have been left in the lurch with your nonchalance.