Android user here. I have five different classes of notifications:
Completely off, notifications blocked. Any category that doesn’t give me actionable notifications or notifications based on something I’ve explicitly asked for is here. All streaming apps and games are here. Any app that tries to send me an ad in a notification gets this treatment. Almost every social media category also gets this setting, though there are a couple notable exceptions I’ll get to later. All notifications that are not important and not urgent go here.
On, but delivered silently and minimized. “Silently” might be a bit of a misnomer here since I rarely have sound on, but this also means no vibration. The notifications are also minimized in the notification shade and go to the bottom of the list. This is where my new email notifications go, because I’ve got my inbox pretty well filtered down and only things that are actionable are allowed to stay unread in the inbox. Basically this is for anything that’s important but not urgent.
Silent. See above for “silent” disclaimer. This section is for notifications that are urgent but may or may not be important; notifications from my cameras, for instance, or headlines from a news org. I also allow selected categories of Mastodon and Lemmy notifications through: only messages typed out by another human, though. Not likes or reposts.
Vibrate/sounds. For notifications that are both important and usually urgent. Text messages, Discord messages (from friends only), Slack messages while working. 2FA checkins. Most notifications from my library. Delivery notifications. The notification that my garage door has been left open (it happens a lot). Also, unfortunately, I have to have Instagram DMs in this category, because my wife sends me memes and they’re always really good.
Vibrate/sounds and override Do Not Disturb. This category is for VERY urgent and VERY important notifications. Messages from family members (though not group messages). Notifications from my alarm system. The doorbell.
I do also use BuzzKill to finesse messages that I think are delivered in the wrong Android categories; like the stupid notifications my cameras always send about cold weather. I know it’s cold, and I know that’ll affect your battery life. I don’t need to be told every time the temperature dips below 40°F, but I do still want to know when somebody is trying to get into my garage.