I'm a fosterer with quite a bit of dog training education. I second the advice that you need a good qualified behaviourist, this means degree level study or above.
However, for the meantime, nobody should be taking anything from him by force. This will worsen the behaviour. The things he's taking don't sound like they pose danger to him so take all the urgency out of the response. It's anxiety driven so you want to make everything really chill.
Firstly, clear everything away, as much as possible get things in drawers or too high to reach. The less he can get that he shouldn't the better.
Work on swapping with a low value item like a toy he doesn't play with much, so say an old ball, give him the ball, get a treat and offer the treat while holding your hand for the ball. What should happen is he drops the ball, give him the treat, then hand the ball back. He's learned that nothing bad happens here. He gets the treat AND the ball. Do this 5 times in a row, then leave the ball with him. He's learned here that it's all very chill and you've reduced his anxiety.
As he gets better at this, increase the challenge slowly, maybe a toy he likes a bit better, then better again. At this point you can also start swapping items, so you take a teddy, give him a treat, then give him a ball. If this makes him anxious then slow down, you want it to be really chill for him.
Eventually he'll start giving you stuff just to see what he can get. It's a fun game.
Another exercise you can try if he does get something you don't want him to have is to throw treats away. If he has something you can throw a treat in one place, then another, then another, while he's having a great time, quietly remove whatever he had, he'll probably have forgotten he had it, but make sure it's quickly hidden to help, give him loads of fuss when it's gone for extra memory wiping!
Also make sure he is getting enough exercise and attention, and he's not in pain, these kinds of problems usually start if a dog is feeling crappy for whatever reason.