Toddler behavior please help

[Strugglingmumtotoddler]

I would be grateful if someone could give me some advice because I'm at the end of my tether's end. DS (3) is constantly hitting and throwing random items at me, DH, TV, dogs, you name it. We have tried everything recommended - getting down to his level, calmly explaining, distracting, cuddles, taking him to the park, time outs etc. he seems to have understood but a few minutes later he goes back to it laughing. The nursery says he is not showing any concerning behavior and generally angelic. He is certainly hitting us much more than anything or anyone. I'm sitting in tears here because he punched me in the arm really hard and I finally shouted at him. I really don't want to be a shouting parent and I feel as though I failed somewhere and that's why his behavior is this way.
He is thriving otherwise, all milestones met, plenty of good food, lots of outdoor exercise, loving his nursery etc.
please give me some advice I'm feeling desperate today.

New Toddler Taming book by a renowned paediatrician Dr Green was my saviour.

I would put him in his room and say he can come out when he says sorry and stops hitting .

This used to freak one of my children out. He much preferred a naughty step from where he could see me. I only tried it twice and it became clear this method would never work as my son was too distressed to reflect on his behaviour. Every child is different

Oh OP, sounds so hard. You are your toddlers safe space, that's probably why they are trying out such challenging behaviour on you.

No expert advice, but know consistency is key. Say the same thing, take the same action, don't withhold love.