I mean I think it is bad writing but this is not normal Thor. This would be King Thor that should be Odin level or so.
We have seen that play out in recent years with the two roughly being on a similarish level.
That said, modern power level depictions are pretty bad. Thor gets a magic Celestial killing axe, Hulk kills everybody and so on.
It is like you need to just take your knowledge that a character exists from run to run and that is it.
But problem is normal Galatus can beat Odin, and this is said to be him at his "most powerful"!