This is a must have Team - Notion, Coda, Clickup, Fibery - all allow this with minimal charge now and note taking is not possible with it
Long notes are messy, difficult to search and sort - this simple function (and I am a soft dev so yes, it's simple) allows high level overview then drill in with the simple function of a toggle or expand collapse
Make it or i'm out, great product don't want to leave, but make or break - bidirectional links would be also great and should have that in this new movement towards 2nd brain and linking notes, but toggle?! You should have done this years ago
Best