How do you completely disable the phone app that is default? Since Samsung doesn't understand that DO NOT DISTURB means I DO NOT WANT TO BE DISTURBED and will stop every active media just to let me know a phone call I NEVER WANTED.
Well, since it's a phone you can't disable the "phone" portion. Have you checked that you don't have calls listed as an exception when on do not disturb? Or, have you tried a Bixby routine? (when playing media, mute notifications or something like that)