There is actually a GameDev competition like you are describing, it’s called the Gimkit Awards. There’s a set of 10 categories, with 1st place people winning up to 5,000 gimbucks. It’s an event ran by me and Unstable, and it will be happening around April of 2025. You can also win multiple categories, so if you’re good you can take home a lot in prizes (this year someone got 15,000 gimbucks off the Gimkit Awards by winning multiple categories.)
You seem pretty interested in it, so stay tuned for this coming april 
(You can start making a map as early as you want for this competition though!)