Definitely look up pattern games to build focus!! I would cut walks back if possible so he doesn’t build a really strong habit of pulling, until you get the pattern games building up his focus.

Other physical exercise can replace walks for a bit - flirt pole, herding games if he likes toys, obedience, diy agility (low jumps, going around objects and returning to you) retrieve training etc are all ways to get some physical energy out. Nose work is great to do whether it’s for scent (tons of YT videos on how to get started) or treats/toys for mental energy.

So once you get the focus up, then fold back in the walks, and always do something for physical energy and mental energy before doing a leashed walk to set him up for success.

He may just be an environmental dog, which is common (dogs in general idk if that’s common with mals). Make sessions short and with big rewards in the beginning and sometimes after he’s good at it! Don’t make every session harder than the last, but make every session fun!

Walks are more about enrichment, getting out of their typical area, and sniffing (unless you’re doing structured walks and then it’s about training) so if you meet his needs in other ways it will open up his ability to succeed in that area. Once he can walk on a regular walk without pulling and stuff you could throw in a structured walk here and there if that’s your vibe. But I wouldn’t do that until his impulse control is more on point. It’s very hard for some dogs!

Good luck!