Another thing stopping the game from launching is microsoft onedrive. Onedrive in some rare cases has taken over the environment shell path to Documents. FTD at this point reports that a mod is breaking the game when it isn't that. If you follow the microsoft answer here: https://superuser.com/questions/1205668/how-to-unlink-my-documents-folder-from-my-onedrive-account you can unlink onedrive from that folder.

If you do want to use OneDrive you will need to do the following.

1, Create a text document in
C:\Program Files (x86)\Steam\steamapps\common\From The Depths

2, Rename the document to SaveLocation open this doc and add the following path
C:\Users\PcProfileName\OneDrive\Documents

When you start the game up it will ask for a profile name as C:\Users\PcProfileName\OneDrive\Documents is empty.

If you already have a From the Depths profile and blueprints, save games etc...You can copy over everything from your PC from
C:\Users\PcProfileName\Documents\From The Depths
and paste into
C:\Users\PcProfileName\OneDrive\Documents\From The Depths

If you pop back in game, you should see that it has loaded up your profile and will start to save anything new to OneDrive.