I do use org mode for writing documents and presentations but I feel like a lot of these 'organization' tools just result in spending more time tweaking them than actually doing the work you set out to organize.
It's deceptive to look at a document like this and think that you'd have to use all of that knowledge and configuration in order to use org mode for planning your tasks.
Much like Rome, this document wasn't written in a day. You can start using org-mode for task planning and agenda with a fresh (Doom/Spacemacs/vanilla)-Emacs install and be productive from the get go. That's what I did.
Then, you add things whenever you feel like it. You may never feel like it, the default is already very powerful, and I don't have a lot of customization around agendas, etc. in my configuration. The only thing I actually do is set where my org mode files live, set a couple of keybindings, and add one agenda view. That's it. I've been using that same setup for years now.
The rest of my config is merely making it a bit prettier, because default Emacs is somewhat ugly.
Maybe my problem is I don't do complex enough work to warrent a tool like this (I'm still a BSc student). I do use emacs for almost everything already but I don't use anything for organization really because it just seems like a really complex way of just setting a reminder somewhere
I use org mode and my work is fairly simple. Never underestimate the power of being able to go back to your thought process on something you did 1, 5, or even 10 years ago.