We'll just have to wait for Android to expose that in an API, it seems. By the way, the apps themselves are not controlling this, except maybe for eBay and Mon

We'll just have to wait for Android to expose that in an API, it seems. By the way, the apps themselves are not controlling this, except maybe for eBay and Monzo (the only two out of 100 apps on my phone). Most of the time I have to go to settings->apps->notifications and customize the sound. Also, for all chat apps I like to have silent notifications configured. Except for Element, which I use for my family exclusively, and that one needs to have a loud and prominent sound. So, eBay and Monzo are leading the way, but majority of apps are still not there and leave up to user/settings/android to control their sound and just default to whatever is the main notification sound on the device.