I’ve compared many note taking and productivity apps, but with regard to easy navigation of documents and their internal pages, Clickup is outstanding. Please give it a try and let me know. Clickup is about to release their version 3.0 which apparently will improve it further. What I like about it, and what I suggest to implement in Fibery, is:
Apart from the left navigation menu in Fibery that lists the spaces and views, it is useful to have a hierarchical navigation menu showing up at the left of an entity that has child entities. In clickup those are Documents with their internal pages, but in Fibery we can apply that for all entity types. (I am against the Documents in Fibery, want them just to be fieldable entities, but was another post already).
Now I understand that in Fibery the frames can open side by side, which is a bit similar but it does not allow to navigate easily through hierarchical relationships.