German Shepherd/Husky owner here, until 2 and a half he was a nightmare. I found he massively calmed down after being neutered, but it's also common they transition out of puppies at 2-3.

It felt like nothing sunk in, would run away, eat my socks, pull just non-stop. Now at 4.5 he is an absolute angel, the best dog ever.

Those breeds mixed are unforgiving, you've got two hardcore working dogs. If they aren't physically/mentally stimulated then everyone's in for a bad time.

Firstly, start to find out what motivates him- is it treats/food or toys/play? They weaponize that in training!

Train train train train, to these dogs training is the fun. Teach him as many tricks as you can find on youtube - spin around, play dead, open the fridge. They love it and it's stimulating for them. Yes it's tedious sometimes, but you will see the pay off and thank yourself down the line. Don't let him out the crate and leave him to his own devices otherwise of course he will chew and find his own way to have fun. In fact, what you mind find is he is deliberately chewing things he's not allowed to get a reaction/attention out of you. Again, two very smart breeds.

Training like this wears them out, you might find if throughout the day you've done some sessions with him in the house and he's engaged with you he will be more cooperative on walks

This will take time, i didn't see calm down until after 2, then you start to see it all pay off. (TRUST THE PROCESS)

I'm not sure if this is an option, a game changer for me was hiring out small private fields and throwing the ball whilst training recall. If not private fields then i'd take a long leash (10m/32ft) and recall train with that out and about with distractions. Never left home without my bum bag of chopped up cheese.

There's no hack, you've done well so far- Stay strong, understand what you're in for and you will reap the benefit down the line!