I was a NEET too, because of physical and mental illness. What I did in 2019, and I think I might get a job soon:
I started that summer (without finishing), this course on freecodecamp:
https://www.freecodecamp.org/learn/scientific-computing-with-python/ 1*
I went into a govt study program to get the fastest certification you can get in the country for this line of work. It´s two years, and you are less than the college people but you dodge the maths and pedantic, useless crap they have to go through, plus 2 years gained. There´s plenty of people that don´t study officially and get work, but the main thing with this would be connections. With this course I am guaranteed access to local startups and companies, which is why I am now in one as an intern.
I also went to class to socialize a little, since I am a friendless, chronically ill incel. It was overall an enjoyable experience, particularly the first year, when I had more in common with people and I hadn´t lost most of my illusions of having a place in the world. I still prefer programming to laying bricks or staying in my parent´s home arguing with people online and masturbating. 3*
So I don´t recommend learning on your own, as a hiki or NEET you will benefit from structured, socialized learning. But you can do it. And the best way to learn is to start something that you really feel motivated towards, and try to simplify your goals and finish it. I started a JavaScript game in 2021 of Bill Gates throwing vaccines at people (lmao) and it looked pretty good but I had to concentrate on my studies. But you will learn a lot with personal projects like that.
// CAVEATS
1* I have to say that if you go and study on a govt sanctioned program you won´t find teachers like this. Expect the worst, Kafkaesque, subhuman creatures that should be flogged and made into fertilizer.
2* This goes into an important caveat in programming. You need to be ready to do everything on your own, learn and everything expecting little guidance and help from physical people (I say physical people because you will be copying from stackoverflow and tutorials as much code as you can, at least as a beginner, I assume). There´s plenty of help online, but teachers and coworkers won´t be a significant part of the help. It´s a lonely job in that sense.
3* Use the first course that you enrol to online (I like the one I provided) to discern wether you love programming, you don´t really like it or you hate it. If you don´t feel like you love it at first, I wouldn´t recommend trying to get into the field. It´s stressful and full of insecure, arrogant males keen at shining at the expense of your 'incompetence'. You have to enjoy programming, because you won´t always enjoy working with other programmers.