your son is harder for you to parent than your daughter, who is more compliant.
I understand that you find him challenging, your expectation of him though, is somewhat unreasonable @Letsgoupstairs
He is a wee, individual, developing, human who has unarticulated frustrations (possibly, hence biting) who may very well sense your own frustrations with him and he feels insecure?
A quiet, compliant, stress-free life with our children is a total oxymoron, just not gonna happen, is it?
For you @Letsgoupstairs, when you get a moment, really think through what is happening here, your darling boy is really no different to all others, he is just being himself and he is not your easy going daughter.
You have issues with him being himself, I'm sure you do not want him to be something he is not, ergo you and only you need to unpick, exactly how to move forward, for the two of you, which will enable you to cope without suppressing his individuality.
I offer this response, purely as a complete outsider which may be totally off the mark for your situation @Letsgoupstairs but may give you pause for thought.
Our children are such a joy but our responsibilities to them are huge and overwhelming sometimes.