I don't think many settings are needed and aggregating creates a ton of non-obvious problems. Remember that opening the Monzo app on iOS at least clears all Monzo notifications automatically.
Both platforms Monzo is developing for have timed do not disturb features. If you don't want late night Monzo notifications, you likely also do not want late night Twitter notifications for example.
Where Monzo could expand in this problem is in sending “non-live” transactions and informative notifications as silent notifications. These don't make noise or even light up the screen but are available to see the next time you pick up your device.
For example, I don't need to know in the moment when a standing order or direct debit goes out without issue and hasn't triggered any other warnings (low balance, etc) but I do still want to be told about it the next time I look at my device.
Same with regular income, I need to be told at some point when it has come in but do not need to be interrupted. A payment from a friend is worth interrupting me for though.
The furthest I would personally go is in soft muting merchants. Telling Monzo that I don't need to be told that Netflix/Spotify/etc. has billed me again this month for exactly the same amount as they always do.