Cat issues

[u/IshiyamaYokkakoUAGEG]

Hello, I have a cat who is about 4 years and a half old. He used go be very cuddly before moving to europe, and he was for a while, but after 6 months, he seems to be having behavioural issues. Usually, he goes to eat random pieces of dust or dry pieces he sees on the stove. Daily, he seems to drink out of the sink, and messes with the dishes. He seems to hiss and get angry when playing with his toys now, and he bites down pretty hard, not letting go of them, hissing when anyone gets near. I am worried about him a lot. I couldn't find any solutions online, so I wish to ask here.

I took him outside recently to see about giving him some mental stimulation, and it works, but he goes back to the same behaviours after 1 hour, or 30 minutes. I love my baby kitty, as he was a very good partner with his brother during hard times, but he is causing a lot of stress for me.

His diet is urinary tract food, mixed with wet food to help his urination, and he also is on teeth brushing medications.

I really would like some advice. I want to work through it with my little guy.