I upgraded our two Start Unlimited plans to Do More Unlimited primarily for the Mobile Hotspot feature. One of our phones is an iPhone 11 and the other is a Samsung S10e.
If the iPhone 11 has both cellular and a local home WiFi connected with the Mobile Hotspot enabled, my remote device (iPad6) gets on the Verizon network when accessing the iPhone’s Hot Spot.
if the S10e has both cellular and a local home WiFi connection with the Mobile Hotspot enabled, my remote device (iPad6) gets on the local WiFi network when accessing the S10e’s Hot Spot. I have to disconnect the S10e from the local home WiFi to have the iPad use the Verizon cellular network. Using a site like danasoft DOT com easily tells which Internet network the iPad is on.
FWIW, our home WiFi is only 6 mb DSL, where we easily get a 30 mb Verizon 4G connection at our home.