Frank,
Helen Merrill with Clifford Brown is a classic! So is Sarah Vaughan with Clifford Brown, timeless music. Agree with your opinion of Doris Day’s vocal talent. Two excellent male vocalist from that era are Billy Eckstine and Johnny Hartman. There’s an enormous amount of wonderful music available as this thread often confirms. I will checkout Jo Stafford "Ballad Of The Blues" this sounds like something I’d really enjoy.
Charles