Same problem here ...
I have a macbook from Mid-2012 with non-retina display. Both the GUI and the ebook-viewer are difficult and tiringly to look at.
I find it hard to understand why apple removed the above mentioned font feature. There are however some geek tips to fix blurry fonts and enable subpixel antialiasing:
https://www.howtogeek.com/358596/how...-antialiasing/
Cheers
Chris