I wrote a Python script where you can type in any two election years and it will give a map of the relative change in partisanship from the first year you put in to the second year. Note, however, that it is a relative change so e.g. Clinton and Biden both won Nevada by 2.8 points, but Clinton won the popular vote by 2.1, while Biden won it by 4.5, so Nevada moved 0 points in raw margin, but this shows up as -2.4 since that was the change relative to the national margins.

https://colab.research.google.com/drive/1MyV4K0m0dHywjSbz17qOE38ju8qauTH6?usp=sharing