on the basis of your really nice and extensive message, what to do now I found the solution!!!
Thank you sooooo much, for your time, energy and advises. I am so glad, that my SIM works another time fine and all is working. And I did not lost much of data, only the Bliss-Starter-App-data, but this is not important.
Here what I ultimatly did:
I installed another time e OS 1.1 - nothing changed
After it I installed e OS 1.2 - nothing changed
Then I installed e OS 0.23 (as it was before the upgrade). After the reboot - I had to entry the PIN of my SIM card :)! And a bit later I got mobile net!!!
BUT: The Bliss starter app had problems: “Bliss starter was closed repetdly → app informations or close the app” I opened the app informations and deleted the Cache - nothing were happen. I deleted the data. And??? Tadaaaaa: It started regularly, only my icons were different positioned in the start display.
The I tested all my apps, if they work and show their normal function - all did, except Signal messenger, messenger from e and the App Lounge - they showed the same behaviour as “Bliss starter”, so first I rebooted - did not change nothing. Than I deleted the data from these apps also, as I did for Bliss starter and they work another time. I lost little data, but in this case no problem and I have them still on a backup.
Finally I have another time e OS 0.23 and wonder if i never could update it, but that’s not my biggest problem. And I am glad, that I did not lose much data and my SIM is working as before:)!
So, thank your very much for your tips, advises and questions! It was really helpful!!!