Simple data models enable surprising combinations. A small collection of pages about Massive Wiki, Obsidian, and Mermaid.js.
We admire the simple data model of Massive Wiki: a folder full of markdown files. It enables collaboration with other projects with similar committment to simple data model: they recommend using Obsidian to edit pages. — Massive Wiki Conceptual Diagram - Massive Wiki link 
When cloud services can shut down, get bought, or change privacy policy any day, the last thing you want is proprietary format and data lock-in. With Obsidian, your data sits in a local folder. Never leave your life's work held hostage in the cloud again. — Obsidian link
mermaid.js offers many languages for different kinds of diagrams. All are similar in spirit to dot and Graphviz. site
GitHub announced support for mermaid.js diagrams in their markdown rendering. — Include diagrams in your Markdown files with Mermaid | The GitHub Blog link
Obsidian also support mermaid.js diagrams. — How Mermaid diagrams work in Obsidian | by Ensley Tan | Medium. medium
Rclone is a command-line program to manage files on cloud storage. — Rclone link