Uhm this came to my mind real quick and I had to give a try for a Fanmade map, sorry for the bad drawing.
Storyline:
A decade after the events of Subnautica and Subnautica: Below Zero, after finally paying your debt of 1 trillion credits, Alterra suddenly sends you and Robin Goodall to a mission to find the missing Precursor race on the planet.
Set on the third mega-biome, The Split System, This area is miles northeast of the Crater biome.
This mega-biome consists of complex biomes, and is a half tropical and half sub-zero area, cause is maybe the fluctuations of temperature. Large groups of leviathan class organisms and passive fauna had migrated to this area due to the Aurora being too radioactive and had taken over the Crater mega-biome. This adventure will be harder as the biomes are more deeper, more dangerous and sometimes surprising, from the shallow depths of the Vine Trench, to the deep Cold Caves, would you take the risk in order to find the mysterious Precursor race and search for clues on the planet?
Split System Map
Cave Map