I know this question has been asked a dozen of times, but it seems that my problem is a little bit specific. My problem is that when running cordova build android I am facing the following:

This seems to be related to the plugin cordova-plugin-crosswalk-webview, which I need in regards to the (still not resolved) problem described here, which very likely appears since having this plugin interim-wisely uninstalled.
In order to fix this issue I downgraded gradle from 6.x to 3.5, cordova from 8.x to 6.5.0 and cordova-android from 8.x to 6.2. - without help.
Here is a list of what I have installed:

And these are my installations:

Note: The folder /Users/schumachergbr/Library/Android/sdk/extras/android/m2repository/com/android/billingclient is missing; not sure this is related or not as the billing error seems to be the second in the row for me...
Any idea what needs to be done here?
I have finally fixed the issue on my own by changing the cordova plugin list, which now looks as following: