I am wondering if it is to do with the early access. I saw on, I think the Larian support page (?) that the games made in early access need to be deleted before playing after the official release (6th for us). This was for PC so I’m not sure if it will also relate to PlayStation.
Hello! You will not need to delete your saves before the 6th, that guide was specifically for PC Early Access players going into the Launch version for PC.
Your saves done before the 6th will still be compatible with the game on the 6th and you will not need to redownload the game.
If the Install failed issues persist I would recommend contacting our Support Team so they can take a look:
https://larian.com/support/baldur-s-gate-3#modal