The identifying test is agency, not attention. Ask whose choices change the outcome; if the answer is somebody other than the person you have been filming, you have a protagonist problem, and it is a common one in brand work where the customer is on screen and the company is making all the decisions.
A protagonist needs three things: a want they will act on, a capacity to fail, and something to lose. Remove the third and there is no tension however good the first two are. This is why aspirational advertising so often features people who appear to risk nothing and reads as glossy and inert.
They do not have to be likeable. They have to be understandable, which is a much lower bar and a far more interesting one.
Who is the protagonist of a story?
The character whose decisions drive the outcome and whose dramatic question the ending answers. Screen time and sympathy are not the test; agency is.
Can a brand be the protagonist of its own advert?
It can, and it usually should not be. When the brand makes every decision the customer becomes a prop, and audiences read that arrangement instantly even when they cannot articulate it.