Thank you for your Question.
It is a challenge to raise kids and bring them up as balanced human beings.
However, What you maybe seeing as disobedience, may not be so, but rather He wants to express his wish and will but the method s/he maybe using could be wrong. To solve this issue, always let your child choose BUT from options that you provide for him. e.g. instead Of leaving it to him what he wants to eat for breakfast (when you don’t want him to start his day with Nutella) Ask: what would you like bread butter or eggs!? This way, the child thinks he is choosing (in reality of-course he is) but under a frame work that best works with you.
In short, it is just to play the right cards so as not to trigger that rebelliousness.
Also, for the hitting, with the above method, you might not get there, but if you do, quickly hold the child’s hand, look into his eyes and in a very calm tone but firm say “don’t do that! It’s not right!” And keep that hand in your hand for a few more seconds looking at him and eventually slowly hug the child. If the child tries to misuse this approach of hugging repeat the same thing... hold the hand, look into his eyes and in a calm Tone say the same thing.
Eventually the child will learn.
If in any case, this method is not working for you, you may want to try playing “cold turkey”
You see, the child is only doing this because he wants to get your attention in a wrong way. But when you don’t pay attention and walk away, the need is not fed and he has lost his spectator. (Although you have to be very careful with the method, just Incase the child wants to severely hurt himself)
On a side note, one thing that most (if not all) scholars acknowledges iS that children mostly do what they see. So if you get your way away with yelling at kids, or being harsh on them, then this is what’s going to come your way.
Best way would be to bridge a communication between yourself and him. One of the most effective method is to enforce that speaking. E.G the child is mad, wants to have an ice cream while he has a cold. He cries and yells and rolls on the floor. The Best way to bring him to calmness would be to calmly look at him and keep on saying: “son, I don’t understand! I want you to stop crying so that I can Hear you properly” once the child stops yelling and crying and starts talking in a better way, listen to him to his content and handle the situation you best can. For instance, take a pen and a paper, note down his choice of icecream(s) on the paper and stick it on the fridge. Say we will have all of these, one after another as soon as you feel better... which ice cream parlor would you like to go to!? And slowly divert the talk towards past memories of ice creams and Other trips and good memories and funny memories etc etc. in the meantime also offer a treat the he maybe allowed to have. To make it more appealing to the child give him options like: do you want half a mars bar or sneakers? (When chocolate is your last option to agree to)
InshaAllah these Method should help but the most effective thing a parent can do, is to pray for the child.
Do refer to dua no.25 on Shahifah al-Sajjadiyah
Kind regards and good luck