Improving product usage

One of my SaaS consulting clients wants to improve product usage beyond new customer onboarding.

What type of customer interview should they use?

Option 1: Buyer Journey
Option 2: Churn/Win Back
Option 3: User Interviews
Option 4: Brand / Perception

Questions to ponder:
👉 Are we building products that solve a real problem for our customers?
👉 What's the problem we're trying to solve?

Answer: User Interviews