I think you have a project with a massive undertaking. You need a team of people to work on this. Have you been looking at this site: https://github.com/jgraph/drawio?

The first features I see that are missing is the ability to define objects using text markups. Properties of the objects would also be defined this way. Dynamic constraints would be defined.

The other feature that is missing or just shown wierd: rounded corners. I put a hexagon down and made the corners round max. It looked like a wierd circle.

Keyboard shortcuts should be configurable. I don't like draw io's keyboard commands. I don't like excalidraw's keyboard commands either. They seem to borrow the concept from the mac or some obscure program. (I use visio.)

Get rid of the pricing thing for now. Also get rid of the online storage scheme.

Add multi user feature using shared link (webrtc?).