Is it possible to draw in Obsidian (with a tablet/touchscreen)? I’d really like a digital app for algorithms work but so much of it is based on doodling graphs and automata and diagrams. I really like the idea of progressive annotation of such doodles with a note-taking app, but I need to be able to doodle in the first place.

Sadly not out of the box im afraid, there is a plugin for that though [1]. This plugin is not as advanced as say onenote, but it works for small things

[1]: https://github.com/zsviczian/obsidian-excalidraw-plugin