Not sure if you’re already aware of this but on AM, tap a band’s name and hit “go to artist”. On that page, there is a star that can be clicked in the upper right hand corner. I believe this then marks which artists you will get notifications from per the settings that someone else mentioned here.

The killing of Apollo (and all others) really rubbed me the wrong way, and I refuse to support companies moving in the direction of forcing ads in front of people.