From my point of view, there's no magic recipe to accomplish a UX/UI review.
A good start could be to define the UX/UI Key Performance Indicators (KPIs), to do that you should address specific questions to your stakeholders (product owners, project managers, business analysts, engineers etc).
An example could be:
- at the moment we have 3 main tasks for 2 types of users, are these tasks fulfilling all the user needs?
- the main task (explain what is about) took about 45" to be accomplished. What about the same task provided by our competitors?
- our website is responsive, what about the design strategy (mobile first, desktop first, browser target etc )?
More the questions are precise and matching the current status of the product more the feedback will be valuable for you to prepare a design plan and to decide on which deliverables you want to focus first (research, wireframes, mockups etc)
I hope it will be up to your alley