The modules one isn't necessarily true. I'm seeing a lot of Angular devs keep things under one module (esp for libraries). I don't think the value of multiple modules has really been realized. Exs: we do this for Angular Material and Ionic.
I can't find the exact article I read where the authors discussed this, but I did find a presentation by Brian Ford[1] that touches on the subject.
[1]https://docs.google.com/presentation/d/1Gv-dvU-yy6WY7SiNJ9QR...