Integrate mdblist.com for ratings from all relevant sites
https://mdblist.com/
Contains ratings from all relevant sites for movies and tv shows. Service also has api access and should be easy to implement. With one integration it would be possible to have all the ratings for movies and tv shows. Ratings are updated every 4 days.
Edit , description from web site :
I would guess that the person behind this is either downloading and parsing the IMDB personal use datasets regularly, or they're using/behind the probably not quite on the up an dup imdb-api[dot]com.