I won't say that. He was really unlucky since the start. Viola betrayed him, otherwise they'd have even never got any info on his plans and could have cornered them suiftly. If not Bellamy(betraying him), Luffy could have never come out of the colloseum. Jorah one shotted half the crew. If not for her stupidity, it would have been in his favor. Luffy's also crew grew significantly stronger than expected and he also expected allies to turn down on Luffy by giving them the proposition of the bird cage game(another unexpected thing). But eventhen, he had someone like Pica as his subordinate whose ability is pretty hax in war periods, capable to handle multiple enemies at once. I even think that the only one who could have defeated him in Dressrosa were Fujitora, Sabo, Law, Luffy and Zoro.
With Sugar that can turn you to toy in one touch. Manshelly's ability to bring you back in perfect conditions at every turn and him himself as a powerhouse with hax moves like parasites and others, it wasn't that stupid imo. He was just unlucky. I'd say the real stupid thing he did however was when he decided to release Law when he could have killed him every time he wanted but hey he never saw Law as a threat to begin with. In his mind, the only threat in Dressrosa is Fujitora and it would end up being a fatal mistake i guess, a mistake any villain make
