1. Every company is, in some respect or another, technically a monopolist with regard to its own products. Indeed if this were not true most would go out of business rather quickly.
2. Different legal standards apply to a company selling a finished product to customers vs a company licensing/selling a partial solution to other manufacturers who then sell a finished product to customers.
If you are interested these two principles are a decent starting point for investigation.
Which is irrelevant because monopoly law considers whole markets including consumers and not individual products.
Google engaged in anti competitive practices by discouraging competing stores. Apple doesn’t have competing stores so there’s nothing to compete against.
The law is consistent in that regard because of the scope of the subject matter.
What matters is if using the monopoly position is used to impede competition.
epic could not prove Apple was a monopoly outside their ecosystem. They could prove that Google abused their power within their ecosystem however.