Syncing two phone numbers to one imessage account
I am an US expat living in Europe. I have a Verizon iPhone XR. I got a local SIM and I want to have both phone numbers on my iMessage account--how do I do that? I tried following the instructions online but they did not work.When I put in my new sim, iMessage read "waiting for activation" and sent me a confirmation code. Then, my US phone number disappeared. So, I try to add my US phone number, so I put in the sim and have a confirm code sent to me. Then my European number disappears. Now, I ran out of codes to be sent. What should I do? I want to have both phone numbers on my iMessage.
iPhone XR, 13