Finally, the day came when YouTube turned off the dislikes counter completely, including for developers. And all the tricks you read about turned into a pumpkin. As always, I am ready to help in a difficult situation.
To solve this problem, you can install the Return YouTube Dislike extension, which is available for all major browsers. Until December 13, it used the capabilities of the YouTube API to get the dislikes counter, but after turning it off, the numbers continue to tick.
How does it work?
The developers of Return YouTube Dislike collected data about dislikes even before the official API was disabled and saved the data. Therefore, some information is based on old data.
The new data is calculated using an algorithm that combines data from the YouTube API, add-on users, and views-to-likes ratio.
As a result, you can see, if not accurate, but close to that value of dislikes under the video.