How to write PRDs for features with a wider scope?

I would not call this as a prd, it should be more of a vision doc on workspace as a product.

Docs as a prod would have some 5 to 10 different product teams working on it. It’s simply not logical to write one prd.

But if you do want to give it a shot: break down the feature into smaller components- instead of trying to cover everything in one document, break down the feature into smaller components. For example, for Google Docs, you could create separate sections for editing, formatting, collaboration, and sharing.

I had to make something similar in my previous org and what I did was similar, the product was a workspace and the doc was mostly a vision doc with intended users, impact, feature lists and roadmap I would hyperlink the feature lists with individual prds and we built a separate project on jira + confluence to better track progress

Use whimsical or draw.io to prepare a canvas first