Can Bernedoodles be obedient or will they always be sassy?

It’s no different than any other relationship in your life. If you understand and fulfill the other’s needs, they are more likely to do the same for you and meet your wants (if that’s what you mean by obedient). 😉

How a dog bonds, behaves and chooses to be around you is not predicated on their breed, it’s based on your relationship and the environments you create for them.