Fully supporting privacy-first approach in utilities like yours. TBH I built an internal tool like this for the company I was working on my previous contract.

It would be great if you add a possibility to change the drawing or font color. Even few presets would be enough.

P.S. Just noticed. You have GA tracking implemented. It doesn't guarantee privacy so I would recommend changing it to PostHog and excluding area from every tracking and sessions recording.

What about digital signatures?