Please do email supportdos2@larian.com with a save before before Meistr Siva's house (or a Dropbox or Google drive link, etc), as well as a save or two after, where you have started to encounter problems.
After syncing, each save is a folder in the '..\Documents\Larian Studios\Divinity Original Sin 2 Definitive Edition\PlayerProfiles\<ProfileName>\Savegames\Story' folder.
In Windows Explorer you can zip a file or folder by right clicking on it/them and selecting 'Send To | Compressed (zipped) Folder' (and similarly in OSX/Finder).
