For anyone still wondering how to clear list of recent calls, one possible workaround accessible currently is via the following ADB command:
adb shell content delete --uri content://call_log/calls
In case you are used to establishing a shell session first using “adb shell”, then you can directly execute the remainder of the command “content delete […]”.
This will delete the entire history of calls under section ‘Recents’ in the Phone app.
Happy peace-of-mind! 