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.
Yeah the problem is a lot of apps dump their ads in the wrong category if they even use categories :(
OEMs like Samsung turn off that ability by default unless you toggle it in "advanced settings". Thank you Samsung!
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