>>93590475But Steven's problem is that he's also projecting motivations and plans on his mother's figure. Lion 4 explicits it very well, Steven was literally deluding himself into believing Rose left traces for him to put together to figure out his "magical space destiny"... except she wasn't
Pretty much everyone in the show projects what they want over Rose. Further complicating this Diamond-murder plot is only part of the course
That's not to say she 100% had nothing to do with it. But i highly doubt YD did it anyway, that would be a very simplistic resolution. Unless they found a particularly compelling motivation