Where are spec/dev discussions?

I am using Ethereum for about 6 years now, for my tiny projects. But now I want to indulge in this project more. Because this is already what future will look like.

In my other open source interest projects, I participate via developer mailing lists. But whenever I go to ethereum.org and look for such resources, I reach a bunch of Discord servers.

I mean in all big projects, like for example Emacs and Linux, Richard Stallman and Linus Torvalds participate.

I want to know where are those lists and forums in which the Ethereum project leads actually participate? And why are they so hidden?