It's worth bearing in mind that the tone of the original Rami movies are vastly different from the modern MCU Spider-man movies, or indeed, the 'Amazing Spider-Man' duology.
Rami was deliberatly going the full camp and melodrama route; channelling the original 60's version of the character that he grew up with (which also plays into why he had no clue what to do with Venom.)
...and Raimi did not want to use Venom in SM3, which were correct instincts, as the character was completely out of place with all that Raimi established. The Sandman plot was the true focal point / heart of the film.
So the rumours about RDJ (and presumably others who’ve died or otherwise departed the MCU onscreen) are not to be believed, according to Kevin Feige: https://www.hollywoodreporter.com/m...99pVzT7Gre4zAPkTe1HnbPwSbkvSJG9Lo72zNMmLTL1Z4
Great news. It would have been a move of pure desperation to bring RDJ (and any other actor no longer associated with the MCU) back to this franchise.