Help with puppy biting

Hi! So I’ve had my puppy for over two months now and absolutely adore him. We got him when he was 11 lbs at 12 weeks and now he’s 22 weeks and 35 pounds. He’s been teething a lot recently and losing teeth left and right. But he still bites all the time! I’ve followed every rule at this point for puppy mouthiness. I’ve tried walking away when he bites. I’ve tried saying “ouch” really loud and taking my hand away (though I think he gets more excited with this). I’ve tried redirecting him to toys. But he still bites so much. I genuinely don’t know what to do. He loves people and is very sweet but when he gets very stimulated, he wants to bite your hand or ankles. He knows he’s not supposed to do it, as when we say “ouch” he’ll then sit down or walk away, but if we pet him again a minute or two later, he bites again. He doesn’t bite hard, but he’s getting a bunch of adult teeth right now, so it’s hurting more.

For context, he’s 30% Australian cattle dog, 15% Rottweiler and a mix of a bunch of other random breeds. We do herding exercises with him and keep his brain busy with kongs and puzzles.

Any help would be appreciated! Just need anything to help with this behavior.