Ignoring that you're underrating Ruiz (just like Joshua and everyone else did), the bit about Fury is absolutely true. I can't argue with that. Nor can I argue with his win over Klitschko being right up there.
It's just the 0 losses argument. Joshua might not have any 1 win as good as Fury's but he has several wins against top, top fighters, each of whom are good enough to beat any fighter on their day, such is the heavyweight division.
Fury has the best wins, but he's only fought 2 guys that could reasonably have beaten him. If Fury fought as many top guys as Joshua did even though he could beat them all there's no saying he couldn't avoid an upset. I mean he's already been close to losing to Wilder, was a ref decision away from losing to Wallin due to a cut, and was rather lucky not to have lost to McDermott.
For me there are many reasons to say that Fury has a great resume, but I can't subscribe to the whole 0 losses business. I accept I may just be different to others here though.