Curbing aggressive chewing?

My 18 month old has always chewed on anything and everything. It's been getting progressively worse though. Nothing we do seems to curb his desire to do so. He goes after furniture, the walls, shoes, his toys, and pretty much anything he can get his mouth on. Any mom's have some tips to help stop this? He's starting to take actual chunks out of his crib and the wall. Rail covers do not work btw. The second we see it, we stop him and tell him no. He is so sneaky about it now 🤦 He's got all of his front teeth and a few back ones. Nothing is coming in right now so I'm sure it's not teething.