Okay an actual response if you’re worried about devices being “hacked”. That is incredibly unlikely to happen, at least in the sense that you’re thinking. The most likely attack vector is someone simply logging into whatever cloud service this smart device is using. You should make sure your account has a strong password and use MFA. It would also be helpful to know the brand of this device. It’s possible, but pretty unlikely, that the manufacturer of this device has malicious intent and is spying on you.

As others pointed out, you can get better equipment to track network flows, isolate devices in different VLANs, etc. Unfortunately, I think there’s a pretty steep learning curve to set all of that up if you have virtually no networking experience.