I installed the app, downloaded adb, enabled developer options en debug facility. Then in Windows 10 I entered in command-mode (as administrator) the following: adb shell pm grant com.zacharee1.systemuituner android.permission.WRITE_SECURE_SETTINGS.
Windows replied with "Security exception: grantRuntimePermission: Neither user 2000 nor current process has android.permission.GRANT_RUNTIME_PERMISSIONS."
And it stopped...don't know what to do now...