You are my man! You are the best! How did you find the time to write even this dev log. Your experience so far is so close to mine. I share all your thoughts. I have made absolutely the same choice for the game engine (because I support and love free (as a beer) software) and the genre of my first game. I like all the stupid 2D platformers that make you just play without much of a thinking. :) One of my favorite games genres is also Metroidvanias, the other is turn-based strategies. I like also real-time strategies, therefore I'm not strong there. :) Good luck man! I've also subscribed myself to this game jam, however I'm really busy in the outside world so I really hope I will be able to make it, unfortunately I have to work only over the nights. My plan is to make simple 2D platformer similar to Mario (saving princesses ;) ) or another favorite game from my childhood is Tiny Toons - Buster's Hidden Treasure (Sega) In my case I'm going to use some free to use arts from OpenGameArt website. In parallel I'm having a popular Godot course from GameDev.tv (Ben Tristem and Yann Burrett).
Good luck!