If anyone has a similar problem in the future, we figured it out! Turns out that vTuber Kit's Unmoving Plaid feature was looking for an image file in the Textures folder that had been deleted. When it couldn't find the file, it was crashing/breaking. Reference image attached of solution #1 that will work for any other users. Solution #2 was to manually edit the save file and remove any lines in there that reference the missing image.
(Though to be honest, I don't think users will be able to find out specifically what image filename vTuber kit is looking for, so you may just have to remove any lines in the save data file that contain references to image filenames that no longer exist in the folder. You can do this by searching for any lines with "unmovingplaid" in them and checking the referenced image name.)
I'll be sure to patch this in the next version so it can't happen in the future.
