The problem you have is that what you learnt is not actually programming and you just think it is. It’s scripting, markup languages and a database. It’s the same principle with the issues most people have when they start learning actual programming and they start with high level/managed languages. Meaning all you learn is writing some logic (which is a good skill of course but it’s just scraping the top of the iceberg), you have exactly zero understanding on how things work on the low level, hardware architecture, memory management, etc etc. I see people declaring themselves software developers when they have trouble understanding something as rudimentary as pointers because all they know is logic and nothing else. Everything else has been abstracted for them by high level languages. And, particularly more so in game development, ALL these things matter.
My suggestion is to stop trying to look for courses on “game development”. Instead learn actual programming by learning a low level language such as C/C++ and x86/x64 hardware architecture with a good book on the subject. At that point you would be equipped to understand and learn everything you want to learn about game development easily because you would not be lacking the foundations. You would not ask “how to save user data to a server?”, which is a rather meaningless question and more akin to “how do I travel from point a to b?” without having any idea on transportation means, using a map or even the existence of your own 2 legs. Instead you would just implement your own solution (either custom built or relying on existing libraries/backends/middleware).