I don't think much of Ruiz. I think he is a disgrace to the sport, but his strengths play nicely into Whyte's weaknesses. Neither of them are good movers, and they both hit hard enough to hurt each other. Whyte can get sloppy when he throws those wide slow hard shots. I think Ruiz's faster hands and tighter punch technique might give him a slight edge.
After Ruiz previous showing, I'd favour Whyte. Ruiz actually seems worse after such rapid weight loss.
I don’t think that Ruiz is a big puncher but he doesn’t have to be to KO Whyte. Ruiz is better skilled and with his combination punching he will land flush on Whyte who IMO won’t be able to take it.
I personally see Whyte scoring a 2-3 knockdowns in this fight personally. He'll fight on the back foot and use his jab and reach. I see the fight going similarly to Whyte vs Rivas, except Ruiz has less head movement and will eat some left hooks. Whyte by UD or MD. I don't see either being KO'd.