Welcome to the forums!
Unfortunately, this is how it is currently. My wife uses my main account login info so she has access to all the cameras and SD footage etc, but doesn’t want any of the notifications, so she disabled the notifications from the app in her iphone. If she were to enable the notifications, she would get the same as me.
Even if you were to share a camera with another user account, that user would share the same notification settings as the main account holder account.
There is a wishlist for multiple shared user permissions, which is requesting different settings allowed for different users of shared devices. I’ll link it below, so visit and vote and comment to help support if you wish.