How to resolve endless iMessage/FaceTime activation loop with eSIM on iPhone 13 mini?

I’m honestly running out of ideas and wanted to ask if anyone here has dealt with something similar or knows how to properly escalate this inside Apple.

Device:

• iPhone 13 mini
• iOS fully reinstalled clean through Apple Devices on Windows
• Italian eSIM (WINDTRE)
• Previously had a physical SIM with another carrier and never had issues

Problem:

Since switching to eSIM, iMessage and FaceTime cannot activate correctly.

Symptoms:

• Continuous popup:
• “Your network provider may charge for SMS messages used to activate iMessage and FaceTime”
• If I press “Turn On”, I get charged SMS fees
• Activation fails anyway
• Number stays with spinning wheel forever under Settings > Messages > Send & Receive
• “Activation unsuccessful” keeps appearing
• Same issue with FaceTime
• The popup comes back after reboot, updates, or randomly

What I already tried:

• deleted/reinstalled eSIM
• reset network settings
• signed out/in Apple ID
• disabled iMessage and FaceTime
• checked date/time
• added trusted number
• carrier verification
• full clean iOS reinstall with Apple Senior Advisor through screen sharing
• waited 24h as requested by Apple

Carrier says:

• international SMS are enabled
• no restrictions on their side
• eSIM provisioning is correct

Apple support:

I spent hours with multiple advisors and Senior Advisors. They initially told me that if the issue persisted after 24h, they would escalate the case to Apple Engineering and collect logs because it could be an iOS/backend activation issue.

But now I’m stuck in a weird support loop:

• they call me
• ask for screen sharing
• say “please wait a moment”
• then the call disconnects
• no callback afterwards

This already happened twice.

At this point I genuinely don’t know:

• if this is an Apple activation server issue
• an eSIM provisioning/IMS issue
• or some weird iMessage registration corruption tied to my number

Has anyone here experienced this?

And most importantly:

does anyone know how to properly reach Apple Engineering escalation instead of restarting troubleshooting from zero every time?

Any help would seriously be appreciated.

[Re-Titled by Moderator]

Original Title: iPhone 13 mini + eSIM = endless iMessage/FaceTime activation loop. Apple Support keeps dropping the case. Anyone experienced this?