If you want to "quickly learn development just to get that shiny software engineer job just because it pays well" - don't. You really need to like problem solving, be passionate about technology, love challenges, love digging deep, analyzing, creating and making stuff work. If you can't tick most of those boxes then most likely you will not like this profession. This trend of "everyone can be a developer" is bull***t and as not everyone can be a musician - not everyone can or should be a developer. Sure you can start as a junior developer at some company and be proud of yourself and try to climb up the ladder, but if you won't like what you're doing you will burn-up and stay as a junior developer for the rest of your career at best. And worst case you will simply waste tons of time doing something that you have no passion for.
Now as we got this out of the way and you really want to learn software development there are many areas that you can aim at. You are talking about back-end and all those Web development related technologies, but have you considered app development, IoT development, Native platform development? Web of course is fairly easy to start at, but you need to pick an ecosystem. There's mainly three ecosystems for web development: Microsoft with .NET, Java and PHP. The easiest starting point would be PHP - it's simple language that has a low learning curve and you can start coding in minutes. There are tons of resources and material to learn from and most popular frameworks used with PHP are Laravel and Symfony. Java and .NET (mainly with C# language) are similar in terms of language and are more enterprise oriented so have a steeper learning curve but probably better job offers too.
Speaking of learning - start small. Code a few basic apps, get a hang of it, feel the code and most importantly learn the code not the language. Principles, paradigms, design patterns and software architecture skills - that what makes you a Software Engineer. Languages shift and change so you need to build strong foundation of engineering skills to be able to pick-up any language and continue building stuff. It's totally fine to look up documentation to check for argument order of some method, but if you've memorized half of the framework API's but can't tell a difference between an interface and an abstract class - that's where you know that you're doing something wrong. Don't look at that AWS or Docker jargon - this stuff will come later... In other words - you don't need paddles if you don't have a boat yet.
Best skill to teach yourself is to know how to learn. Create challenges for yourself, try out some code kata's, try many different libraries, languages, frameworks and don't just use them - reverse engineer them, learn how those work, how they were built and why. Read the code - it's as much as important as writing it. Get to know this craft from the core and all those SQL, REST, JWT, BLAH abbreviations will start to make sense as you go on. Have the best of luck!