How to make notification sound a long ringtone?

[CreaseCrown]

How do I use a ringtone for my notification sound on an app? I understand how to do different sounds for individual apps. But not all notifications sounds are in the list just short ones and I need it to have a long ringtone

[nekogenesis]

Have you tried putting it in the notification folder? The song you're trying to use? That's how i got mine