2y4mo son won’t stop hitting/grabbing other children

This has been going on for more then 6 months now, and everything I’ve read on hitting says it lasts “ a couple months or so” My boy is an only child so far (due in December with second) and I’m a stay at home Mum. We do a ton of sensory activities at home, my son is pretty well behaved, I am consistent with boundaries, he rarely tantrums and only for a few seconds usually. I offer choices and decide for him if he refuses. We get out to playgrounds/indoor playgrounds/activities regularly. We have play dates regularly (although his hitting has now impacted one of my closest friendships so we’ve stopped that one now)

I read the book “hands are not for hitting” to him. I am consistent every time he does it, I will grab his hands and say firmly “No hitting, hitting is not okay, hitting hurts” I apologise to the other child and ask if they’re okay. I usually stop it before it happens but sometimes I’m Not fast enough. I point out the other child is crying and they are hurt and now we have to leave. If he is trying to attack a kid for no reason I move him to a different area sit him down and say “you need to be gentle, if you hit we will leave” and follow through. I talk about what was happening when we are alone and offer words for him to use next time. I feel like I am doing EVERYTHING in my power, reading all the advice online, and still the hitting continues. Sometimes we have a good streak and right back to a bad streak. It makes me want to not take him around any other children, I am embarrassed by it. I don’t know what to do anymore, why doesn’t it stop?

Also my son sometimes tells me he will hit a child if they are using something he wants (even though he hasn’t used it yet himself) I tell him no that’s not okay and remove him from the playground or activity when he does it. Like I said around grown ups he’s amazing. He loves animals, he loves his soft toys, but he hates other kids.

What can I do? At what point isn’t this normal? He’s a completely normal toddler aside from this. Please please help!