Do you think you actually need the "depth module mk 1" to explore the jellyshroom caves? WELL YOU DONT, just hug the ceiling and use a repair tool bruh u can get everything u need quite easily.

This does require a degree of skill but you should be fine

Also other fact for those that read this far u can put o2 tanks in ur inventory so if u put a bunch u might not even need the seamoth at all, just swap 'em