For your Verizon phone you need to turn off TravelPass. You can’t do this from the app but you can do it from the Verizon website. If I recall correctly this was hard to find but it is there somewhere. If you don’t turn it off, it will activate automatically. Otherwise from your questions you seem to understand the eSIm quite well. This is what I do, it might not be the best but it works for me. Turn off TravelPass. Buy the eSIm and load it on your phone using the code. To do this I open the email with the code on my iPad then open the camera on my phone so that the code loads on the phone. Don’t activate it till you arrive. Get a GoogleVoice number. Give this to anyone who might need to call you in an emergency. Before you depart, turn off data roaming on your phone. I just turn off the Verizon SIM (Primary) completely in Settings/cellular. When you arrive, activate your eSim, this will be the Secondary in Settings/cellular. Turn data roaming on in the Secondary. If you need to make a phone call use Google Voice or WhatsApp or Skype. You will have to deposit some money in GoogleVoice or Skype. Every evening when I have Wi-Fi at the hotel, I turn the Secondary off and turn the Primary on, with data roaming turned off on the Primary and Wi-Fi calling turned on. This will download any voice mails, your phone log and any messages from your Verizon line. Then switch back to having Secondary on and Primary off.