Gonna echo what others have said here from my general programming experience: you need to start WAY smaller. Build, for example, a top-down sprite art single-player extraction shooter. Once you’ve gotten the hang of the general problems with real-time gameplay, then move on to the next project.

I don’t think you’re wrong in starting with a particular focus and expanding the scope as you gain experience, but you’ve set your starting point aggressively too high.