Android 15/16 does allow you to control notifications even lower, at the level of notification category, but indeed the app must have chosen to use them.
Most apps that are in need of notification control either:
a) bundle everything in one category, from critical notifications without which the app can't fulfill its purpose to "HEY YOU HAVEN'T USED ME IN A DAY, USE ME NOW" spam
b) create a new category for spam every time they feel enough users have turned off the previous one, which is often
DoNotNotify gives granularity and rules (which a specific app may have chosen not to implement).
For example: