The best book you’ll ever read? That’s a bit of a stretch but everyone is allowed their opinion.
I feel it’s long-winded and, for the most part, incredibly slow moving. The novel would have better been a 180 page western romance novel series than a 900 page behemoth.
If you feel uninterested in reading a western novel, consider that it’s primarily a character drama, and would be just as good if the setting were space pirates or whatever else.
I spent 5 years living near where Mr. McMurtry lived and wrote about - flat and boring as can be, but holy moley did his writing ever romanticize that area’s history effectively.