This is a plugin for the unity ripping software AssetRipper. It fixes a lot of errors in the ripped output and makes the play mode usable.
1. Download the GUI version of AssetRipper
2. Download SubnauticaExportHelper
Create a folder named "Plugins" next to "AssetRipper.exe".
Extract the content of the downloaded SubnauticaExportHelper zip in this folder.
Start "AssetRipper.exe"
Change the "Shader Export Format" to "YAML Asset"
Click on "File/Open File" and open your Subnautica.exe
Wait for the program to load the game
Click on "Export/Export all Files" and choose your desired output folder
If the "API Update Required" window pops up click "I Made a Backup. Go Ahead!"
If the "Missing AssetBundles" window pops up click "Yes".