Three songs, three different briefs
A wedding has at least three musical moments that want different songs. The processional is short, usually instrumental, and needs a clear, unhurried pulse to walk to; two to three minutes of piano and strings at 60 to 70 BPM is the classic shape. The first dance is the emotional centre: a three to four minute ballad in 6/8 or a slow 4/4 around 65 to 75 BPM, with both names sung and a final chorus that gives you somewhere to end. The reception wants energy, a singalong chorus and the guests' names if you are feeling generous.
Because the generator writes from a description, tell it which moment the song is for and it will shape the structure. A first dance should build, a processional should not. Ask for a gentle intro on the processional so the doors can open on a quiet bar rather than on a downbeat.