BB King always had one problem he never could get past. He could not sing and play at the same time. When he is playing, he is not singing, and when singing, he is not playing.
Singing and playing guitar at the same time is not easy at all, especially if there’s a funky beat or syncopation.
I can play guitar, and I can sing almost adequately, but to do the two together I have to practice the hell out of both parts individually, then practice the hell out of doing them together.
Something like this is about as hundred times as hard as it looks: https://www.youtube.com/watch?v=16kHVpwFE5g