Hmm, does this extend to the Internet connection? Would using a work wifi for your side project mean they can claim to own it? What about public wifi? In order to keep your project safe, do you have to get a cellular connection and VPN into your home network?
It's not explicitly about hardware, software, internet connections or food -- the particular items that you are using are irrelevant. If you are using company resources to produce a thing, they have a claim on the thing produced.
Sniffing into any type of connection is feasable, expect if it's your own (Mobile Network). But they can still control your notebook how they want, take screenshots, etc. Because the software within a notebook only needs internet connection, the control, policies, etc it's centralized and pushed to the software in your desktop with any internet.
It's not just "buy a notebook".
If you really want to cover all bases, don't even do the personal work in the office on company time...even if you are using your own laptop.