I love how people like to say things like Broly and Kid Buu destroyed galaxies by destroying planets one at a time, like there are no such things as stars, and also that Bibidi and Broly somehow live very long.
In Broly's case we see the galaxy destroyed on the screen as King Kai watches in horror. In Kid Buu's case we see his Ki enveloping the galaxy in a flashback, after seeing planets get destroyed, in addition Supreme kai said "galaxies", and Kid Buu did not know IT at the time, and was constantly sealed and resealed by Bibidi. Kid Buu may not be a one shot galaxy buster like Broly as it can't be proven, but he has to be close, otherwise the timescale is just too ridiculous.
As far as this battle is concerened; feats indicate Broly withe ease, but logic dictates it being alot closer as Broly is shown as clearly more powerful than ssj2 gohan, but in a less convincing manner than fat buu, ssj gotenks IMO was weaker than fat buu pre and post ROSAT, so I still go with Broly.