My brother claims to have achieved that transformation with GTD. My personal experience is that complex rigid systems like GTD require high initial investments in effort and can be brittle. They are sort of like doing a total rewrite of a codebase. My biggest wins have come from making small incremental changes.
The biggest win I ever made was getting a small filing cabinet (a banker box works, too) and putting it, a stack of manilla folders, and a marker next to my desk. Then, when I get a piece of mail or have a piece of paper, I file it in the appropriate folder, making a new one if need be. If you have a huge, chaotic pile of papers somewhere, try this. Take that pile and throw it in a box somewhere. Don't try to organize it. You now have a Pile-Of-Papers-In-a-Box. From now on, instead of putting new items on the POPIB, file them in your new proper file system. And if you need to dig something out of the POPIB, when you're done with it, file it away instead of returning it to the POPIB. Soon, the POPIB will shrink to a pile of mostly trash that you can store in a shoebox in the back of a closet.
My biggest loss was trying to digitize my home office with a fancy Fujitsu scanner, Google Drive, and Airtable. It turned out to be a bigger project than I anticipated, and I prematurely abandoned my trusty analog system. Soon, AI will make this trivial, but for the time being, I'm sticking to paper. I also prefer the user experience of physical paper, at least until I can hand over all the paper shuffling to an AI.
Other small gains I've made are using Obsidian on my phone for notes and using Google Calendar religiously for all appointments and scheduled activities.
Filing cabinets, digital calendars, note taking apps--these are all simple, obvious things, but I think being organized is all about acquiring a handful of these small habits and sticking to them. If your system is simple enough to become reflexive, you'll be more likely to stick to it under stress.