As far as guidelines, I have spent time looking as well an never came away with a good answer. One useful website for comparing some of the best tools is https:

As far as guidelines, I have spent time looking as well an never came away with a good answer. One useful website for comparing some of the best tools is https://text-to-diagram.com/ https://text-to-diagram.com/. My personal favorite is D2. Still lacking a few layout features that I want, but it gets me 90% of the way there. The syntax is great for projects big to small, and it strikes the perfect balance between "create a diagram fast" and "feature rich". But in terms of actual guidelines, I would agree with another user that C4 actually tries to lay out some sort of guidelines.