Overexcited puppy on walks

So I have a golden retriever puppy who has just turned 6 months old. He’s never been overly great on his lead and harness but has gotten much better.

He’s reactive in terms of when he sees another dog walking towards him he pulls like crazy and wants to go say hi.

His new favourite thing is, when we walk past another dog and don’t let him go over to them because he’s pulling, when the dog has walked past he will then jump up at myself or my partner and try to nip us and then will lay on floor and bite his lead.

Please no judgment in terms of us using a harness. We are going to start slip lead training soon as i know it’ll be better for us all.

But just wondered if there is any initial advice for his overexcitement when a dog has walked past and he jumps up to bite us?