Sounds like you have a good plan lined up.
I think a better idea would be to start making smaller games. How about trying to make a game in 1 month? Spend 1 week on designing, then 2 weeks on the game itself, and 1 week for polish. If you start doing that, and make 4-5 games, you will get a far better idea of how to approach game dev, and possibly make something more fun.
I don’t know your current experience, this advice is best suited for people still learning game design. The numbers are random(ish), and depend on the amount of time you can invest into that. This exercise helps understand that games are not something with infinite scale, where features are being added endlessly for years.
I’m not sure why, but the idea of working on a game only for as long as people enjoy it sounds wrong, but that could be just me. Some games are late-bloomers.
I will admit that my approach to game dev is more art-based, similar to drawing on an empty canvas. My ideas possibly wouldn’t work for someone approaching game dev from a business perspective. It’s up to you what your aim is, and what you consider success. Don’t forget to have fun with it, users can see if the dev had fun making a game and would love to have fun with them :)