If you work on something small and simple on a constrained timescale with a set deadline first—like a Pac-Man clone, or an Arkanoid clone, or a Vampire Survivor

If you work on something small and simple on a constrained timescale with a set deadline first—like a Pac-Man clone, or an Arkanoid clone, or a Vampire Survivors clone—it will take you longer than you would've expected, but it still won't take too long, and you'll come away from the experience with some code you can reuse, some ideas of how to do things better next time, and a ton of confidence due to having explored the problem domain somewhat. "Punching above your weight" and taking on an experimental or otherwise complex game design for a game development project is a good way to learn, but it can be frustrating and you can get burned out when you run into unforeseen design and implementation issues. I think this is the way most people go about independent game development, and it's how I started out when I was much younger, too. "Punching below your weight" and choosing a smaller-scoped project—ideally one with a predefined and tested design—is extremely underrated. Unless you've done something like this many times before, it might seem "beneath you" (especially if you have some ideas of the ideal long-term game project you want to work on that you're excited about), but it's actually a great way to solidify your skills (especially your design skills, as you play around with modifying an existing game design once you've implemented the basics of it), and prove to yourself that you can finish something you set out to do. Plus, in the process, you might find something unexpected in terms of either tech or design that you can take with you to your next "real" project.