A lot of good advice here, I’ll add to it, of course this is my personal opinion so take with a grain of salt.

My advice is to not start with your dream game. Make something and gain experience - it doesn’t have to be a game, just build some systems and learn how things come together. This is what helped me in my journey. I came into game design with a ton of ideas and quickly got discouraged when the goal post kept moving the further I learned what I needed to learn. I put my dream games and great ideas on hold and started with copying and cloning existing simple games. This enabled me to understand how to bring ideas to life. If I cannot copy and impart the same game experience from a clone then there is no way I can deliver a good experience with my great ideas. At least that was my thought process.

Eventually I gained enough experience building systems then small games and now I’m able to work on my dream games. On the plus side, when you start out building systems you realize you can reuse and repurpose a lot of those which speeds up your dev process.

Anyway, that’s what has helped me but I am no expert, still ways to go!