I'll say I appreciate you taking the time to get me to understand your situation a bit. To clarify, 5 years ago, it was much easier to get a developer job with less experience and less knowledge. Now there is a much higher bar, even though a year ago, there was a high demand for developers, BUT the bar is now raised. A lot of this is because of the emergence of coding bootcamps and the popularity of software development careers in general.
So again, there is unfortunately much more competition and much more to learn and apply to have a stable career in tech.
As for what to practice and learn, I would start off with what you learned from your actual interviews you've had over the past few years. Remember what questions they asked you, and the ones you couldn't answer well. Find out those answers and truly understand why the interviewer even asked you those questions in the first place.
Remember that the job of an interview is to tell that a company is hiring a COMPETENT person who they perceive can do the job. When you can't answer people's questions, they don't perceive you as competent or a good candidate and will find someone else. Your job is to learn how to be competent, to answer common interview questions (basic programming, fizzbuzz, system design, data strcutures and algorithms, etc). You need to be coding more, like literally everyday. There are many coding practice coding sites where they will give you some typical coding problem and you can practice to implement them. Then you can go online to reddit or what not and ask people to review your code. This feedback loop will help you improve and further your chances of not only being a good developer, but ultimately getting a job.