Can’t Customize Different App Notification Sounds

Why does Apple not allow me to change the notification sounds/ringtones for different apps? (I am talking about apps OTHER than the 8 iPhone ones you can customize in Settings>Sounds & Haptics.) I have a work app that I’d love to set as its own unique tone in order to distinguish it from ALL the others that currently use the same tone—from across the room, I should be able to know it’s my company app notification. This is something I could ALWAYS do with every Android phone, but Apple locks these customizable features down. Anyone know a back door to this??