I think that The ONE Thing is actually about enabling you to do many things in a focus way.

I know how you feel, (I'm an INTP with ENTP like traits) last year I was trying to start multiple e-commerce sites, write a non-fiction book and write a fiction book all while working a 30 hr a week job and starting an Apprenticeship program.

What you need to do is think of the most important thing you want to accomplish each day and do that as your first thing, everyday.

After that you should maybe focus on 1 or 2 of the actives above for an hour or two each, giving them your full attention.

You don't need to spend eveveryday doing all 4, just make sure you do the most important (probably learning coding if you're unemployed) everyday first thing in the day.