Hi @jonhathoni
I already tried several different approaches (reset smc, boot in safe mode, ...) and multiple reformats. I think it's a hardware issue because the lighning conector doesn't have the led on, the same charger works fine with another macbook.
I've just installed macos high sierra once again so I'd like to prepare this workaround at least to have it functional.
I think my problem could be solved with applescript and some UI skills. I have used Front Window Analysis Tool Using AppleScript System Events (get window elements) but I cannot see the buttons with that tool 
any help is really appreciated.