So I know what that feels like. To have a child who is constantly - as in every waking moment - pushing your buttons.
I don't know if there's any solutions to this behaviour apart from consistent boundaries. A steady and firm application of the rules. Also I would make him earn time on the iPad for good behaviour. He shouldn't just get the iPad by the by.
Hug him as often as you feel able. Tell him you love him as often as you can too.
I know it sticks in your craw when he's been beastly but when you look back in seven years, you'll be so glad you gave him this affirmation.
Had I not had three other children, I would have thought this behaviour normal.
My ds, now 14, was very difficult. An angel at school. Very academically able.
Constant rages from the age of two until 10.
Violence like throwing his car seat around, smashing toys, throwing and smashing remote controls, kicking cars.
Damaged his bedroom twice by tearing out light fittings, spraying ink everywhere.
General hostility and would never ever do what was asked of him. Asking him to get dressed or clean his teeth would provoke a rage.
We were all so depressed and lost.
My dd, two years younger than him, detests him now because of all the distress he has caused her. He can't stand her.
My GP didn't believe me. We paid for two counsellors over the years. They didn't make a difference.
He still makes us late for everything because I think he needs to have a feeling of control. I lie about when we need to leave now.
He's still surly and a bit hostile. He now sees a male counsellor once a week. I know he cherishes that hour.
It's so hard. He was constantly told off for his poor behaviour. And now he's very defensive.
For your sake, find a counsellor if you can. GPs aren't really helpful and CAMHS is stretched to the limit. I think your ds may be too young anyway.
Make sure you get rest yourself. Look after yourself.
It's very tough. It must be bad for a parent to feel so negatively towards their child. You have my every sympathy in this situation.