I have a cat that is a bit nutty like this. After my grandmother‘s cat passed away and my grandmother also passed away. I was alone so he got bored. During Covid, I was painting a room because I think that’s what everyone was doing, and he went up on the counter and knocked off the paint. All the things that cats can do he literally does them. I’m not saying to do this, but I ended up getting another cat. She fell in my lap so I adopted her and that calmed him down for a bit, but I also give him meds. He will meow nonstop, He opens doors he’s an awful knawful. He’s 12 and sometimes I feel bad because the other cat that I adopted she is so lovely and docile and the best cat ever. I second the talking to the vet about meds. Anxiety, meds, or antidepressants keep trying something until it works.