I have found that sometimes this works and sometimes it doesn’t work. The eSIM gradually lost connection. To keep the eSIM connected I had to turn the Sim off.

How would that work with a second data e-sim?

Is this a bug? Seems kind of strange for this to be happening.

Yes it must be some flaw. I called Airalo about it and the technical help said that this was normal and I had to turn the sim off, but I know from my own experience that is not always the case. On other trips I was able to have both on.

iPhone IMS uses the data of the 2nd esim for WiFi calling.

Unfortunately that is not happening...

But you said above you had your primary SIM (VZW) turned off?

That SIM should be left on, with data roaming toggled off and WiFi calling enabled (assuming that is a carrier supported function).

Calls and iMessages should, in theory, work then.

Leaving the VZW eSim on, with data roaming OFF and WiFi enabled would still get the "daily travel pass" SMS.

I tried every config, VZW eSim on would always get that message

That’s interesting. My carrier (and previous carriers I’ve used) only charge on usage on that sim (data, text message or voice).

Turn TravelPass off. You have to go to the website to do this, you can’t do it from the app, I believe. I don’t know if this will allow you to do what you want but it will stop TravelPass from automatically activating.

Travel pass deactivation instructions. I have never had a plan with this type of service as active.

Any roaming odd worldwide roaming partner will interfere with IMS on my iPhone if my phone connects.

how do you set this up? What are the steps to take?

At least for me, I do a manual network selection to a network that I know the sim can't register on. That usually does the trick.

Unlocked iPhone XR or newer with updated iOS
WiFi calling on
Set primary sim to data roam off
activate 2nd data sim using WiFi on arrival

To check the iPhone lock status: settings, general, about, lock status “no sim restrictions”

Your primary sim cannot have an international plan feature like the Verizon Travel Pass as discussed above. ATT has roaming partners in the Caribbean which has messed up my IMS.

Why does it matter if the primary SIM has roaming so long as you select a carrier that does not allow roaming from your home carrier (as described in post 643 above.)?