I tried using Obsidian, but I could not resolve the uncertainty of what should be a separate note file vs several items inside a note file.
I then tried various 'outliner' applications (Dynalist, Roam, Workflowy). With these kinds of apps, there is hardly any friction between document and content granularity levels; everything can be just one big tree / directed graph.
I finally settled with Dynalist [1] -- it recently introduced backlinks and is the far more mature, sleek and feature-rich option compared to Roam.