As long as back then, those Divine Kings were truly willing to pay the price, actually, even if they wanted to lift all the divine restrictions on Zhou Tian's subordinates, it shouldn't have been an impossible task.
But…
Although, by the abilities of the Divine Kings, if they were willing, the problem of breaking the divine restrictions on Zhou Tian's deities wouldn't have been an issue. Even though Zhou Tian wasn't an expert in divine restrictions, to break those restrictions would inevitably require paying a certain price. Obviously, without necessity, those Divine Kings would be reluctant to pay that price.
