I read your doc. And can give you the following input.
How would you get the first 1k, 10k, 100k users? I don't see anything mentioned about a clear marketing plan. I get it, you want a non-profit and all that, but how do you plan to get users on board and start generating content for free? What's in it for them? There needs to be some kind of incentive for them to switch to your platform. Especially in early days where there is not many users and readers, who wants to post quality content on a platform with 100 users or less?
Taking actualized.org as an example, it took years to build for Leo. It says 29,145 users and Copyright © 2013-2023. Now there is a lot of free content generated by people over the years, but Leo has his Youtube channel through which he has reach and can attract people to register and participate on this forum. So you need people with a huge follower base to be on board, and they most likely won't point people towards your platform for free. Or somehow rank well on search engines, which also takes time and SEO and some content to begin with.
Hope that helps.