im not sure if this will help but this is how I fixed the issue, what I had done is I had to reinstall both Bannerlord and its modding tools because I mod had messed up being able to start a new game but my mistake was that I had reinstalled it onto my second SSD rather then my first original SSD which is where I had previously had the game installed in. So I just reinstalled the game and editor toos in that first SSD where I had originally downloaded both the game and editing tools and the problem had fixed I got my terrain back.