Very valid concern and something even experienced candidates have to deal with. At initial stages of your career, you need to study the most popular products in an academic sense.
As an example, I wasn't an Instagram user and had a low opinion about the content of the app. But I realised that was costing me a successful interview. So I studied how it works, what are the features, what are the competitors features. What works differently for Instagram vs Sharechat. Why are the user based different.
At senior levels, the questions move more towards strategy and behaviour.