Please email supportdos2@larian.com, with a description and your latest save (or a Dropbox or Google drive link, etc), and one before the final fight, if available.
Each save is a folder in the '..\Documents\Larian Studios\Divinity Original Sin 2\PlayerProfiles\<ProfileName>\Savegames' folder. In Windows Explorer you can zip file(s) and folder(s) by right clicking on it/them and selecting 'Send To | Compressed (zipper) Folder'.
