you can't selectively turn off junk notifications from apps that you need notifications from..
i want to use the peets app to know when my coffees ready but it spams me with pumpkin spice latte deals..
Unfortunately, companies know most people aren’t like us so they keep pumping out the crap.
You can't if it's a junk app. Many reputable apps today have properly described notification channels and you can turn them off selectively (under android at least). That's what I did for my banking and several other apps. Every "marketing" channel was turned off.