When you look at all of the genres that vote, Adele still has the best shot at AOTY with Sturgill at a close second.
It's hard for R&B albums to win AOTY because it's hard for them to get votes from genres like Country, Alternative, New Age, Contemporary Christian, American Roots, Classical, etc. With Adele having appeal in those categories and getting votes from pop, etc she still has the best chance of winning. Plus she had a huge hit in Hello to raise her visibility.
Though Grammy voters might look to make a political statement and break for Beyonce. It'll depend.