Obsidian.md is a pillar in the modern "Tools for Thought" space (along with logseq and Roam Research). Obsidian's plugin ecosystem is enormous, and features robust, bidirectional integration with Excalidraw. Notes in your diagrams, diagrams in your notes... combining text and visual/spatial sketch and whiteboard tools is profoundly powerful.
https://github.com/zsviczian/obsidian-excalidraw-plugin
Now there's also ExcaliBrain which builds on Obsidian's graph view:
https://github.com/zsviczian/excalibrain