My new rescue pooch

[WhiteRabbit]

I expect your dog is just excited to go for a walk, and as you said he has a lot of energy, so he wants "to go!"
He lived in a bathroom previously, so it's understandable. Head collars work well if walks are problematic. Also - you can frequently and suddenly turn around and walk in the opposite direction. Remember to praise and reward when he walks with a slack leash.