This is exactly my experience. I bought an AT&T iPhone12 from Apple (paid in full, no lock), and wanted to activate eSIM on Verizon. They kept recognizing the IMEI #2 as a Physical SIM in their database and could not generate an ICCID. I had to go get a physical SIM, activate it, then did the process to transfer to eSIM with help of an agent (although I'm not sure I needed their help in the end). Then I had an activated line on eSIM, but data was not working. I had to insert the AT&T physical sim and then data started to work on Verizon w/eSIM line. I could then remove the AT&T physical SIM and data would continue to work with Verizon on eSIM.