If it's any help or hint, the scanning adds the very first folder (with thumb) to the library, but no files are in it and then never gets further.
Downgrading to a clean 9.3.2 did nothing to fix issues.
Testing 9.3.0 shortly and lastly rolling back to 9.2.6
Downgrading to a clean 9.3.2 did nothing to fix issues.
Testing 9.3.0 shortly and lastly rolling back to 9.2.6