There is low alamos chess that is this variant with knight instead of bishop and without castling.
But anyway, removing knights from the game make the queen have all the game moves.
"But you could just add knight moves to queen making her a amazon"
But then the king will not be a simplified version of amazon.
"Ok, but if that is the problem you just add knight moves to king too"
Then the knight move the king to will not be a simmplfied version of the kngiht move queen do.