Thank you for the additional information. It is helpful.
It is hard to stop a dog that is chewing on things at this age as they have been teething. The good thing is that he should be done teething very soon and his need to chew on things should be reduced.
It sounds like you have provided your puppy with lots of appropriate things for him to chew on. They have wonderful chew toys that you can put treats inside or peanut butter inside that helps the puppy keep focused on that chew toy rather than your table legs or other inappropriate objects. One problem is we tend to give them all their tools to keep them happy but dogs grow bored with the same toys that are always available. So you need to separate them into groups and only give a portion of the toys at any one time and rotate them about every week or so. This helps a dog stay interested in his own toys. You need to keep objects off the floor that are off limits and out of his reach. This can be hard if there are children’s toys on the floor so it will take a lot of effort on your part to keep the floor free of these objects as much as possible. With his reach, keeping things out of his reach even on counters might be difficult. Keep some storage boxes with locks available for this purpose.
No can be a powerful tool so you can stop the chewing at least long enough for you to remove it. You can also use a product called bitter apple on surfaces that you do not want your dog to chew on. It has a bad flavor that most dogs do not like. Hot pepper sauce can work as well for this purpose.
The best way to stop the chewing is to crate him when you are not around. It may not sound like the best solution but if he is ingesting items, it is for his own safety. Dogs can develop obstructions ingesting foreign objects and that can be deadly and expensive as well. Crating will definitely protect your home and Rex. At his age, he should be able to be crated and able to hold his bladder and bowels for up to 8 hours.
If he also chews on things when you are home, you can get a basket muzzle for those times he is out of his crate but you can not keep a close eye on him. Basket muzzles allow a dog to breathe normally and even drink and eat to a certain extent but will help protect many item from being chewed. Remember when taking something away from him to substitute something he can have.
You can train him to ignore some items as well. For instance if he chews shoes, you put a shoe on the floor and leash your dog. Each time he goes toward the shoe, you give a short tug on the leash and a firm NO. When he hesitates and doesn't go for the shoe, praise him and reward him with a tiny hot dog sliver (high value treat). Do not use store bought treats as dogs work better for hot dog slivers. He will quickly learn that ignoring the shoe gets him treats and will start ignoring them. You will do this for items that he seems interested in. It won't eliminate the need for you to crate him initially but will teach him what items are definitely off limits to him and will help him not touch those once he is totally through teething.
I hope this information is helpful to you. If you would like any additional information or have more questions please don’t hesitate to press the reply to expert or continue conversation button so I can address any issues you still have . As I mentioned, I'll be leaving for an appointment very soon so my response might be delayed. If you do find this helpful, please take this opportunity to rate my answer positively so I am compensated for my time.