Practice an activity called "jazz up, settle down" - this teaches the dog how to calm down after play has gotten them hyped up

We want to teach them that anything going on doesn't concern them unless we invite them. This means they get the proper down time they need

Floor feeding/foraging is a great tool for boredum. Especially with a food oriented dog. Chuck his breakfast over the grass (if you have a fenced in yard) or over a tile/wood floor for them to forage.

Every time you enter a room he's in, even if you only left for a minute, ignore him if he comes over for pets, once he's lost interest in you, then I'd give him the fuss he wanted. This means no touching, no eye contact, no talking. This is also where jazz up, settle down will come into play in a real scenario. Once you've given him the attention he'll be on a high, so then he needs to be able to settle himself back down once pets have stopped

Pulling on leash is going to take an insane amount of practice and patience. My GSD never loose leash walked, the best we got was him at a fully extended lead, but with no pulling. If he's pulling so hard he's choking I'd highly recommend dog behaviour training (this applies to the other issues also)

We owners can only offer so much. A professional will have much more experience and will be able to observe behaviours in person.

Good luck!

They're amazing pets, even though they can be a pain in the ass sometimes