After a long session with adobe staff:
Thanks to all trying to solve my problem during the last hours ! The aim was to find a way to transfer raw/dng data from iPhone to LR classic WITHOUT having a chance to contact the cloud (f.e. in a mountain retreat). After hours together the solution is: You need an external stroage connected to the iPhone - in LR mobile go to "export as" check "original" or "dng" and as destination of export click the app coming with your external storage (f.e. Transcend). Then the pic observing the rules of iOS is transferred into the "sandbox" of your external storage. Connect the external storage to your laptop and you easily import the dng files into LR classic. I think, we had a good and contructive common solution finding - thanks to all - photoWD