can you elaborate on the phone basis with engineers? I can’t really imagine how that wouldn’t be much more hassle discussing details without written documents, so I’m intrigued

The way NASA did it for decades was conference calls. Nowadays it's Teams meetings.

The outputs of the meetings are decisions that are later encoded in very many very long documents. It's just faster to hash out engineering details when the relevant engineers are able to talk to each other in real time and relevant decision makers are present to be able to unofficially bless or reject what the engineers come up with (formal acceptance of these decisions is of course a paperwork thing).

So, in this domain anyway, it's not a literal phone call. But it's what we see as the modern equivalent.

You do both, but I know at work for me the problem with written communication is we just talk past each other. Writing is, still, a very distilled and compressed medium. Meaning, a lot of the information is lost when translated to writing. I've spent weeks talking over email and on ticket just to solve it within 5 minutes on a zoom call.

A picture paints a thousand words