Expert reviews evaluate products from a distinct perspective, and offer a view of an UX expert. This approach judges the product in terms of trustworthiness, credibility, competency, reliability, design and style.
This is a heuristic and self-exploring approach to understanding the product and provide an analysis about its strengts and weaknesses. It is indeed opinionated. Since heuristic review cannot be quantified, it has to be applied carefully.
How to conduct expert review
Once you have a deep understanding of UX design and its processes plus you have a deeper experience designing applications you might have a good overview of UX design already. This means you should feel comfortable conducting an expert review and provide a valuable feedback.
You need to evaluate the product from A to Z, including onboarding, usability issues (by spotting missing common design pattern which most like produce usability issues).
In order to make the review more accurate, you should pair it with other research, particularly quantitative research.
TODO: Read and implement the following resources