Nearly everything you said is straightup wrong.
First, jinx is also a very strong champ, or was at least, so you will get no sympathy points for that.
Second, Darius is not a tank and is no where near unkillable...especially if you simply dodge his slow, very telegraphed, relatively low ranged, double counterplayable Q....
Third, Velkoz is not broken, and I say that as someone who mains darius, who gets stomped by vel. And decent assassin or diving bruiser or mobile adc absolutely destroys vel. And any mage with even better range is super safe, and any strong tank with high HP and decent resists can easily survive a vel combo and even CC him during ult to make him near useless. He has lots of counterplay.
Fourthly and last, this is the only one that you were partially correct on. Pyke is indeed a pos champ, but he is no tank lmao. Not even one of the tankiest. He certainly has a busted kit that covers and makes up for his squishiness, but he is no tank. If he is CC'd and bursted, he will die if he's not massively ahead, especially late game when the other team has caught up in build. A real tank won't die near as easily when caught. Pyke's problem is his stupid ult, insane mobility to make plays even when he messes up, to escape easily when caught, his strong and virtually guaranteed CC, and his insane regen when out of vision. THOSE ARE HIS PROBLEMS. HE IS NOT A TANK lmao.