asking beforehand for good resources on how to compose in a specific genre is the way to go. just submitting something different instead doesnt feel like youre trying to understand this genre imo.
i cant link you a tutorial on how to compose dungeon synth, since i dont know one. if you dont know the genre, dont submit. if you wanna make something for this theme, ask questions regarding that. just going like "this is not dungeon synth" at the beginning of your description doesnt really help.
something like "i tried to do dungeon synth but i got this instead, pls give me feedback on how to improve this entry to make it sound more like the theme" would be better
"Also everything in life doesn't have to always fit in a freaking box to be acceptable as good behaviour."
no, but as part of a musical contest with specified rules, i dont think its good behaviour to intentionally break these rules.