You have your timeline backwards. Opera was the first browser to implement a built-in native adblocker in 2016. Here is the blog announcement: https://blogs.opera.com/desktop/2016/03/opera-built-ad-block...

Opera was and actually continues to be a pioneering browser with many "firsts" over the years. I was an avid user of it for a decade but I am saddened that it has become surrounded in controversy with a shady Chinese owner and predatory loans and stopped using it two years ago.

https://www.engadget.com/2020/01/19/opera-accused-of-predato...