Your network provider may charge for SMS messages used to activate iCloud / iMessage and FaceTime

Although this issue has been raised multiple times in the community, I’d still like to bring it up again. I have the same situation as described in this discussion: Your network provider may charge for SMS … - Apple Community

Want to add, that I have two carriers: Telekom (Germany) which is the main one and set on a usual SIM card, and Vodafone (Ukraine) on eSIM which I am struggling with.

My assumption about why this happens:

1. I can see in "Settings > Apple account > Sign-in & Security > Email & Phone numbers" that my number is unavailable for iMessage and FaceTime and you must have a SIM associated with an Apple device for "+380...my number" to be used for iMessage and FaceTime.
2. In "Settings > Cellular > SIMs" my Vodafone number doesn't show up in SIM menu, which is actually also very strange. Furthermore, in contrast to my Telekom SIM, I can't edit the number manually.
3. In both "Settings > Apps > FaceTime" and "Settings > Apps > iMessage" lists of how I can be reached there is a updating sign near my Vodafone number, which means that Apple constantly tries to connect it to the FaceTime and iMessage, what, as far as I understood, might be a reason for those pop-ups. Interestingly though, this hasn't been ending for almost a year, because I get the pop-ups during the same period of time. There is also NO possibility to stop this updating. When I choose "Remove number from iMessage and FaceTime" by clicking on my number in this list, it disappears at first, but as soon as I go out and back to this menu, appears again.

A lot of my time, effort, and nerves have already been spent. What can I do here?...