If you're an indie dev working during your free time, then trying to produce a game with tools you don't find interesting will just result in you making a bad g

If you're an indie dev working during your free time, then trying to produce a game with tools you don't find interesting will just result in you making a bad game, or never finishing it. You'll learn a lot from writing things from scratch, and likely come out of that a much better programmer. This experience can lead you to making a more interesting game. The difficulty of writing a custom engine is also overblown, you don't need to (or should) implement a general purpose engine. Just implement exactly what you need for your game. Anyways there are plenty of recent examples of very successful indie games using custom engines, often from a single dev or small team. Sure you may be able to get your game finished faster with Unity, but there are thousands of garbage Unity games on Steam, you can always add one more to the pile.