Remember, we are specifically talking about the action of belief,
No, we're not. We're talking about the belief in the existence of the teapot. Pay attention.
Let's take two people, Alice and Bob. Clara asks both of them if such a teapot exists. Alice says "I don't believe that teapot exists". Bob says "I believe no such teapot exists." Which of the following statements are true: (1) "Bob believes the teapot exists" (2) "Alice believes no teapot exists" (3) "Alice believes the teapot exists" (4) "Bob believes no teapot exists".
If that's still tripping you up, how would Alice and Bob each answer the question "Does the teapot exist?" with a simple "yes" or "no".
I don't believe. In anything at all. I have zero beliefs. [snip] This is the only trace of "belief" you will find in my entire being. I believe in nothing else.
Nonsense!
Your problem is that you think that belief means something like "belief without reason" or "belief without evidence" or whatever other nonsense some youtube personality fed you. You like to think that you're above such things, some perfectly rational being, accepting only the assumptions necessary to function.
This is what happens when you get your "education" from blogs, forums, and youtube instead of a university.
Unless you're completely delusional, you'll soon come to discover that that isn't even remotely true. Even worse, you'll find that you actually DO believe things without reason or evidence -- most things, in fact. Go ahead, give it a bit of thought.
See, belief isn't subject to the will, after all. You can't choose to believe or choose to not believe in things. Give it a try. You can say it, but you can't actually force a change in your beliefs. (This isn't to say that beliefs can not change. For example, you could be convinced or otherwise compelled in to changing a belief.)