So as of right now, Dragon Ball Super Goku has a 4-A tiering and the reason is:
"Multi-Solar System level with Super Saiyan 3 (Stronger than when he fought Kid Boo, while in Kai, Kid Boo gradually obliterated a galaxy)"
I have a few issues with this:
1st: It uses Kid Buu Kai's feat, which shouldn't be counted as a real feat for the character as is an anime-only thing and Dragon Ball Kai has the costume of being inconsistent with the original material
2nd: Kid Buu is NOT 4-A, for the following reasons "This profile strictly uses the original manga for scaling the characters. Please don't try to use feats or statements from Dragon Ball Kai to upgrade them, as Kai contains contradictions to the source material", this is a quote from Majin Buu's profile itself so, yeah
Conclusion: Yeet 4-A Goku out of existence and just make him higher as SSJ3