Some new app was selected, downloaded, installing forever. Cancelled it.
Then in the update list the top app downloaded - installed forevver.
I Uninstalled the app.
Back to google Play: The next app update - installing forever. Other downloads are all pending.
I uninstalled several seemingly offending apps, this did not help. The same behavior repeated, just the next app in the updat list got stuck.
I finally discovered a hint: Settings - Apps - Google Play: Open it, clear cache.
While there I cleared all caches whose names began with GOOGLE.
It helped. Please benefit if you have the same problem.