I had the same issue with my Renault Espace once. Turned out that a simple small bracket was broken that held the windowpane in place. When I repaired it, I had to guide a wiretapped metal flexible rod through a piped area in the window mechanism far enough, otherwise it would have stayed in the down position as well.
I did a yt search and found this, but my guess is that you already saw this...
https://youtu.be/sT-cgqgzogw