build in app.
I can confirm that on the new sony android 9 phone, when i try to select a ringtone, no ringtonepicker will show up instead you have to install one from playstore first. 1 sound is already factory installed, no more. After i installed a ringtonepicker you be able to select other sounds
It's not bound to android 9 or 10.,but to sony/samsung. Trying a few other devices on Genymotion a got a Standard Phone with android 9 which shows the standard ringtone picker.