I don't know much about Playstation, but do you have any way to delete everything (Cyberpunk & saves) on your PS4, reinstall the game and import the saves to the PS Cloud ?
Frankly, I don't see why you can't use them (especially if the games are from the same region).
Having a similar issue-had the game at launch, then I refunded and deleted. However, after reinstalling I've found that instead of using my old saves, my PS4 just creates a completely new save file. I am also unable to download my previous saves as nothing shows after I select Upload/Download Saved Data. It's as if my PS4 recognizes Cyberpunk as a different game, and thus is unable to use my previous saves.