My Carrier Says That My Samsung Galaxy S10+ Is Not 4G/Volte Capable. What?

Having the same problem, also with Consumer Cellular. Mine is a s10e and is also on the AT&T list saying it is approved (though indicating it may need a software update). Have spoken to a couple reps who say they can do nothing as it is a Verizon branded phone (unlocked).
Does anyone have any insight into this? Will flashing the firmware with a more recent version help? Or, is it a matter of CC not wanting to help as they did not sell the phone?