I seem to be in a similar/same situation. Missing all origin story voice acting at least. Afraid to continue and unknowingly miss other gameplay audio. Verified game files through steam, deleted and redownloaded the "...\Documents\Larian Studios\Divinity Original Sin 2" folder and relaunched, moved installation folder to another SSD (same drive as the OS now, was on another internal drive previously), and then just started from scratch and reinstalled the entire game. No dice. Same issue.
