I honestly think Ruiz would KO Fury , Fury does not have power he is quick at moving but Ruiz has fast hands and would do a better job than Wilder did .
Fury will run rings around him using his outrgeously longer reach and beat him in a comfortable but boring decision is my guess.
Fury would keep him at range and make him look like a fool with feints and arm punches like he always does with smaller opponents. It would be similar to the Chisora fight, Ruiz can put his punches together better than Chisora but it wouldn‘t matter because he couldn‘t cut off the ring against Fury. Ruiz has fast hands but he has slow feet and Fury with his ring iq wouldn’t be dumb enough to play into his cards like Joshua did.