SUMMARY
It seems that Android 10 changed storage access, making KDE connect unable to receive sent files to default "/storage/emulated/0/Download" path. It fails with error, the following is seen in logcat:

    1-26 18:54:55.564  6617 13058 W DocumentFile: Failed to createFile: java.io.IOException: Permission denied
    01-26 18:54:55.565  6617 13058 E Shareplugin: Error receiving file
    01-26 18:54:55.565  6617 13058 E Shareplugin: java.lang.RuntimeException: Cannot create file boarding-pass.pdf
    01-26 18:54:55.565  6617 13058 E Shareplugin:  at org.kde.kdeconnect.Plugins.SharePlugin.CompositeReceiveFileJob.getDocumentFileFor(CompositeReceiveFileJob.java:267)
    01-26 18:54:55.565  6617 13058 E Shareplugin:  at org.kde.kdeconnect.Plugins.SharePlugin.CompositeReceiveFileJob.run(CompositeReceiveFileJob.java:140)
    01-26 18:54:55.565  6617 13058 E Shareplugin:  at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:462)
    01-26 18:54:55.565  6617 13058 E Shareplugin:  at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    01-26 18:54:55.565  6617 13058 E Shareplugin:  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
    01-26 18:54:55.565  6617 13058 E Shareplugin:  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
    01-26 18:54:55.565  6617 13058 E Shareplugin:  at java.lang.Thread.run(Thread.java:919)

When I tick "Customize destination directory" checkbox and select Download path, the path is shown as "/tree/primary:Download" (check the attachment screenshot).
This way it works perfectly fine, the file is received successfully.


STEPS TO REPRODUCE
1. Install KDE Connect on Android 10 smartphone
2. Pair the devices, try to send any file to the smartphone


OBSERVED RESULT
The file could not be received with an error.

EXPECTED RESULT
The file is received successfully.


SOFTWARE/OS VERSIONS
Android 10, KDE Connect Android 1.16.0 from F-Droid.