Google has been working hard on staying ahead of the competition and while the old Edge browser had Reader Mode, Google Chrome lacked one. Chrome did get it later but the feature is still not complete and is hidden behind a flag.
Google, however, is improving the Reader Mode and the latest Canary update adds the ability to customize Reader Mode. With the new update, users will be able to customize the Reader Mode. Google will allow users to change the font, switch between light, Sepia and dark themes, and even change the text size.
The latest update is just for Canary users and we expect Google to roll out the feature to the public in the future.