I feel you have made the decision

and would like to go back :-) since "跟大老板很合拍，很受大老板賞識。 跟小老板性格不是很合得來，做事方式不是很一致".

If I were you, I definitely would go back to challenge myself and be prepared for the failure. It is a good opportunity to test if you can do what you think you can. As obviously you want to be the decision maker. If you fail, you will learn and become a better leader or the worse case you just back where you are.