I am basing my feedback on my understanding of musical tropes - but music is also self expression and a jam is a pretty low-stakes environment (unless you are participating in a professional capacity and you have clients following along... so probably low-stakes ;) ) so do what feels right and if a piece about the deep wants to be made, make a piece about the deep.
You call yourself a beginner - if you want help, further feedback between jams or some tips and tricks, feel free to participate in the Discord. People from the absolute top of the results page have been quite active there so far, so there is a ton of knowledge and experience available there.