I don't think chess engines are a solved problem for some use cases. Yes you can make something strong, maybe even the strongest, but can you create a chess engine perfectly tuned to actually teaching a player? Instead of superhuman perfect lines and inscrutable long-horizon strategy, can you teach nearly optimal human play in a way that's actionable, modular and memorable? Can you improve on tournament prep for players against particular opponents or within a particular metagame?

Also, obviously it's your life, and we're here on Earth to fart around, but I have spent a good portion of my life dipping into one hobby after another, as my dad did before me, so I'm half speaking to myself when I ask this: why do you think you can't meaningfully contribute to any of these realms, even now? To me that sounds like some deep seated fear or doubt, some aversion to competition, some overriding bitterness. I'm slightly worried you'll just be back here in another couple of years trying to find another new hobby, unsullied by the efforts and achievements of others. You won't find that! I would actually suggest a particularly expensive hobby: going to therapy. Try that, and learn that you're already enough, and if your contributions are meaningful to you, that's all that matters. Happy to be way off the mark here though.