Ask HN: How to build one of those collaborative whiteboards?

I'm looking for a new hobby project after taking a coding hiatus and thought it would be great to try and build one of those collaborate whiteboard things (like Figma's FigJam and plenty others).

I'm curious as to what everyone thinks the best stack would be for something like this. What sort of technologies are used for actually drawing to a zoomable canvas?

I have experience with React and Angular, but I've never worked on a project that requires this type of frontend. I assume there's a bunch of websocket work involved but that seems like the easiest part.

What sort of tech stack are these things usually built with?