Market research primarily focuses on the "market." It usually looks to identify what will get prospects to convert to customers.

Strategic UX Research primarily focuses on people's experiences. It doesn't focus on whether someone is a prospect, a customer, someone who uses a product that was purchased elsewhere, or even someone who benefits from someone else's use of the product and doesn't know the product exists.

Strategic UX Research is agnostic to the market. Market research is ignorant of the experience.