Identify types of views
This is just a visual redesign, right? You'll need to align with product initiatives and potentially solve some interaction problems at the same time, but a visual redesign is less involved than a feature enhancement.
This is roughly how I would approach it.
- Break the views into like categories, eg views that share templates or follow the same pattern.
- Work with the Product Manager / Owner to identify your highest priority views and look for any other changes they'd like to make at the same time.
- Work with Engineering to consider the estimated complexity of modifying each view type and validate that you've correctly identified like things.
- Estimate your time to research, develop, and user test designs for each key view within the general types. You'll be establishing a pattern to follow.
- Compare the intersection of product value, engineering effort, design effort, and business alignment for each view to create your priority list.