I'm a solopreneur. Thank you for seeing it as a massive project :) I don't have a plan to do that, but I want to form and run a small community.

I started this project using Excalidraw, but I started it because it was uncomfortable to draw professional diagrams. I'm the developer who created StarUML and I have experience with commercial diagram software.

Most of the features you mentioned are under planning. DGM have the ability to define custom shapes through constraints and scripts (https://docs.dgm.sh/guides/shape-properties/#advanced-proper...), but it's not matured yet.

Thank you for your opinion.