A simple trick that worked for me (Android 8) : if you upload the audio file right in the special folder “Ringtones”, just aside “Download”, “Documents”, “DCIM” … etc (under /storage/emulated/0), you’ll see it appear automatically in the Phone ringtone pick list, at step 5 (without need to “Add ringtone”).
And it works the same for “Alarms” and “Notifications”
I have a couple of Nougat builds*, and the ‘Adbvanced’ option doesn’t appear in the sounds menu. It has a ‘Phone ringtone’, but that has only ‘OK’ and ‘Cancel’ buttons
I added the ringtone by copying the file to the Ringtones folder as descrined by @jpmeuret above, but it would be good to know if the described way can work for Nougat builds.
Thanks
Pete
Officlal e-0.7-n-2019112732147-dev-condor running on Moto E (condor)
Unofficial e-0.7-n-20200117-UNOFFICIAL-suzuran on Sony Xperia Z5 Compact (suzuran)
When you say ‘Soon most of the ROMs wpld be upgraded to Pie’, does that include ROMs for older supported phones (e.g. Moto E Condor which currently have Nougat-based ROMs?