Filter/Whitelist for notifications/messages

Notification settings only show "text as bitmaps"

That's when you press the gear icon on the Bangle.js card. Tap the 3 bars icon in the top left, then Notification Settings there.

Any idea/solution about the sleep time frame as well?

There's a qmsched app which allows you to put the Bangle into a 'quiet mode' at certain times of day - that should do it I think?