I agree with all of this particularly the post by https://itch.io/profile/anothercastle (i hope i've linked that right) but if you already have experience in these areas you could focus on parts that you prefer and really enjoy. I have been prototyping lots of ideas for years now as the best part of making games (in my opinion) is in the problem solving, starting with no idea how something works then gradually figuring it out after problem after problem, then if you wanted to further down the line you could combine what you've been working on into a larger project, it's often the case small ideas bloom into larger ones, this is just my opinion though and mostly everyone will have issues in this regards at some point.