1) Can you explicitly prove that Odin was more powerful than Thor even when amped by the belt of power? Or that the difference of strength was as still as massive as normally? Is not like Thor cannot reach Skyfather level with the right amps, after all he did defeat Glory (who was as powerful as a Skyfather) by fusing his soul as Donald Blake with Jane Foster.
Feats, Odin has feats which are a lot better than Thor with any amp has ever done.
Anyway, in all circumstances Thor was only able to made small cracks and holes in the Celestial's armor, nothing indicate that the Celestial was been harmed, so his examples cannot be used to disprove the validity of the fight between the 3 Skyfather (Odin, Zeus and Vishnu) again Exitar, as well as Odin + Destroyer Armor again the Celestials.
The Blasts of those 3 SkyFathers didn't even brought a scratch on Arishem but Thor cracked Exitar's head and Exitar is as powerful as the entire 4th host combined. That is definitely PIS.
2) Ok, even if Galactus and Odin are equal in power, this is only in the case of a Moderately Fed Galactus (which had mostly Multi-Galactic and Universal feats), not Fully Fed Galactus.
Fully Fed Galactus never existed and will never exist
3) Aside the fact that he had
BFR the Eternal Flame, the Eternal Flame had the power to destroy all Nine Worlds at once only during the Everything Burns series, where it was amped by the energy collected by the Manchester Gods from all the Nine Worlds.
Odin manipulated that Flame, he didn't BFRed that flame.
.4) Yggdrasil be infinite doesn't mean it must have infinite space-time, this could also means infinite 3d space as well like the Void from Dishonored. The other link doesn't seen to work.
Yggradasil spans Space-Time (as I posted above) Space-Time are Infinite. Yggradasil contains 9 INFINITE Universes and Universes are 4D due to Time. So, it is definitely above 3D
5) A
dying universe that was going to disappear by itself without Uthana, i seriously doubt such feat can be considered trully Universal+.
Uthana was powering that infinite universe, so he must have infinite power. Not to mention, Every Universe in Marvel is infinite/boundless. This makes all 9 Realms Infinite in size and also makes Uthana's Universe Infinite too