Tangenetially related, but check out Kaptivo Solo. It's (currently) free and does a great job of enhancing video of you writing a real physical whiteboard so it can actually be read on video calls. Of course, this requires you to have a physical whiteboard, but since I'm attending a lot of meetings in my office, I am fortunate to have one opposite my desk and it works great.

https://support.kaptivo.com/hc/en-us/categories/360001386698...