Steve Shirripa and Michael Imperioli kind of touched on this on one of the TALKING SOPRANOS podcasts. They didn't go into detail (I think Steve wanted to go there but Michael redirected it) but Steve mentioned how Deniro didn't fukk with the Sopranos and I think he hinted at Deniro not wanting to work with anyone involved with the show.
That's lame and disappointing of De Niro. Weird too cuz De Niro has acted in a lot of hot garbage for the last two decades - he'll do Dirty Grandpa but won't work with Rourke/Bautista/Sopranos actors?