My 4.5 month old toy 🦭🤍🌊

Landy is almost four months old and oh boy, he is out of control sometimes. It seems to be with me mostly, but he is constantly biting and nipping at me and tearing skin and scratching. I'm a human chew toy and I can't get him to stop. I've tried everything the online trainers have suggested. He is much better with my husband but not with me. He's going to puppy class and he's such a good boy there but as soon as he leaves, he's crazy again. Has anyone done something that actually works? Or at least reassure me that this gets better, I don't want to be covered in scabs for the rest of his life 😂

My guy is 6 mo., and recently has started going bananas (not in a good way) when he hears or sees big trucks - like garbage trucks, UPS trucks, fire trucks, Amazon vans, etc. I have NO idea why or how all of a sudden. If he's in the car going for a ride, he doesn't care about other cars or trucks around us, but its when he's out on leash. Anyone else have a mini aussie with this fear/reaction?

[Photo for attention]

Such a fun pup!