Then two years later, F/GO and CCC came, and suddenly Gilgamesh can defeat Amaterasu Tamao or at least above her, which means that Gilgamesh is actually above a Servant that at full power outside of the Universe and axis of time.[\quote]
You mean Tamamo? The fox servant you can choose inthe game? She is never at her absolute full power. Ever. If you mean her godly counterpart Amaterasu, she wasn't at full power, not having all of her tails. And even then she only claimed that her full power could destroy thousands of planet's, not a universe. And a claim made about a power she was admits to not even being at doesn't really mean much..
Well as explained above, that doesn't really mean much? And Ameratsu herself isn't a servant, a far less powerful version is, so even if Acrueid at full power is above Tamamo the servant, that doesn't mean she is even close to Ameratsu. And iirc, Nasu also mentioned Gilgamesh could beat full power Acrueid despite technically being weaker than her due to his abilities.
So no actual statements, feats, or even presentation or word of god to suggest planetary level of destruction let alone even remotely close to universal then? I mean, none of what you mentioned have ever shown to be even remotely close to that level of power in any version of servant they have been here...