Audio is really hard unless you have a great system to check it on. I can usually get mine pretty good because I do audio stuff for work so I just make my games in my studio and can really tell what stuff sounds like even on a really short timeline. If you don't have that luxury you almost have to just send it to some friends to get that "it isn't quite right for xyz reason" feedback before you submit it. My biggest tip for using Audacity is "don't" but I do understand that it's free so that's a HUGE benefit. TBH unless you need custom sounds you may be better off using library sounds and finding a setting to "normalize" them so the source files all play at the same volume, and then controlling the volume in Godot. This isn't flawless, however, because of how humans perceive loudness; Loud dialogue sounds way louder than a loud rumble, for example, because our ears are tuned to focus on sounds similar to the ones we make. It'll get you part of the way there, though!
Anyway, like I said, great job. I really thought your entry was charming and in the context of a game jam I frankly prefer to see something unpolished like this more than something that looks and sounds amazing because it was created with premade assets.