With the aggressive behaviours, you may have tried this already but in case not, the following has been helpful for us:
As soon as DS pokes you the first time, immediately give him 100% of your attention. Stop cooking, turn off stove, get down on his level and use a calm, slow voice. Narrate aloud. "I can see you need something right now. I wonder what that could be ... I'd like to help you feel better."
Don't try to guess or get him to articulate, he probably won't be able to, but you're modelling aloud for him a process of noticing his dysregulation and trying to think through what he needs, over time (time!) he may pick it up for himself.
Don't make too much eye contact, stay facing him but eyes slightly down and just glance at his eyes every now and then to check in.
If he immediately hits or pokes you again, keep slowly and neutrally narrating "You hit me again, I think you need to hit right now. And I need to keep myself safe, I don't like being hurt. So how can we look after both of us? Hmm ... (pauses help, assuming he's not in full-on blind aggression). Can we find something to hit that's safe? (Go to the sofa and model punching some cushions, don't tell him to do it too, let it be his choice if he initiates trying it.) "
There are lots of other things you can try in the early stages of aggression once you know your child's sensory profile. My DS responds v well to mini trampoline with loud music on repeat. My DD likes being wrapped in a blanket and bounced on my lap while I sit in therapy ball. Or she likes throwing things hard so we have a basket of soft items she can throw, and beanbags she can throw herself around on.