I more or less did the same thing with the first jam I joined. I submitted a really bare-bones game with an extremely simple idea after learning the basics of Godot. So I don’t think this is a bad idea at all tbh.
For a Jam keep everything simple. I mostly use them as a testing ground while working on my main game to get ideas and to drive traffic. My first Jam isn't even done yet but I've submitted everything it finishes about the time this one starts.