Correction: This was a clear "beginners mistake". But I somewhat expected this to "auto fix" after some reboots 
I actually had to force a check for addon updates which then offered a new version of "Inputstream Adaptive". Now everything seems to work just well. Thanks for the new beta release.
I've just updatet do the lastest Beta.
At reboot it just told me that "Inputstream Adaptive" is incompatible with this version of Kodi and it was disabled.
And now I keep struggling with getting it updated somehow. So far no change to get Inputstream Adaptive working again.
I'm on an Raspberry Pi 4.
