We have two batteries dedicated to the camper and they charge when the engine is running. Would that address the concern about producing energy all the time?
You are the only one who can answer your question there, and possibly only with experience.
Extra batteries only allow more storage. They don’t increase the rate of power production or reduce the rate of consumption.
You need to think about how long you will be parked, at what consumption rate, and then how often and how long you will drive, at what production rate.
For many people, the parked assumption is “forever” so the solar is sized to overcome consumption rate each day, and battery sizes allow for the number of days of sun impairment before you have to charge from a running engine. There are threads on here that go deep down that particular rabbit hole.
I would take a more practical approach. Buy as much solar as you can reasonably afford and fit on the roof plus a few portable panels. Adjust parking and driving habits as needed, consider changes after a year.