Ooh ballad discussion. I'm here!
I always thought Gaga had a super good ear for 'classic' melodies which sound like evergreen songs since the start of her career, as showcased in some early ballads, notably "Brown Eyes" and "Speechless". Not to mention the unreleased gems from the time such as "Let Love Down" (gorgeous!), "Fooled Me Again", "Wonderful", "Oh Well" etc. Even the Stefani Germanotta Band song "Wish You Were Here" is a beautiful example of that. She really tends to shine on piano ballads, whether you like these or not.
"Dope" is one of my faves from "ARTPOP", so raw and effective. I'd say "Joanne" was pretty bulletproof, "Angel Down" in particular is one of my absolute favourite Gaga deep cuts.
"A Star Is Born" was very much a mixed bag when it comes to the ballads - "Shallow" and "Always Remember Us This Way" are excellent and have that 'timeless classic' feel while I can barely recall a note of the rest. Her recent balladry efforts are generally just not as strong and lack that special something, "Happy Mistake" being a big exception.