I have worked in numerous setting in which an entire team had to develop more than one product, or a rather big product (or product line due to proper domain scoping).
There were questions as to the scope of one particular backlog: Should it span just one "tiny" product (like a microservice for "Orders"), or a user-centric product (like a webshop) which internally has requires orchestration of sub-products (and/or sub-teams), or should we model the backlog around an entire team (which was usually the way it went)?