[Milhouse]

and

ln -s ~/.kodi/addons/inputstream.adaptive/lib/libssd_wv.so ~/.kodi/cdm/

Why are you doing this? It's not in the installation instructions for widevine, and is the wrong location (you'll be linking to an out of date add-on for these test builds).

And why do you have inputstream.adaptive installed in ~/.kodi/addons when it's already installed in the build somewhere else?

Delete the inputstream.adaptive add-on you've installed, delete /storage/.kodi/cdm then reinstall widevine as described in the first post - there should be no need to do anything else.