My main motivation with diagram.codes is to provide a set of very simple DSL's so non technical users can use it to create diagrams for easy concept visualization in tutorials, papers, etc. ( Non technical target audience means having minimal configuration options or syntax that can be confusing)

Besides the tipical uml/graph/tree categories I'll be adding different ways of visualizing concepts and relations. Things like https://www.diagram.codes/d/onion-layers, https://www.diagram.codes/d/stack and other experiments not yet published.

I've used most of the tools you listed and there's some overlap in functionality. Maximum flexibility is not my goal (simplicity is) so I'd still use them if a high degree of customization is required.