I simply just draw in excalidraw and take a ss and past it in my obsidian note, I have a setup that automatically parses posts from my vault and then pushes them to my site
Protip: select the items in the canvas you want in your SS and 'copy to clipboard as PNG' instead of a screen shot and you can get transparent PNGs of diagrams or of detailed subsets of a larger diagram easily.
I use the Obsidian Excalidraw plugin, means I can add diagrams to notes without leaving Obsidian.