So after 100 combinations of "ot reset" "ot factoryreset" "ot dataset set active ..." and "ot dataset commit" the esp32 otbr keeps it's dataset in NVS.
I now have a working embedded ESP32 ethernet thread border router 🥳. I obviously prefer this to apple/google/amazon cloud connected thread border routers.
Now i need to design a case and retire the otbr haos add-on and USB radio. And automate the build process in #forgejo CI.