The Penance Stare vs these guys

[The Drunkard Kid]

Galactus was literally poisoned when this happened. It's a pretty big asterisk. Later, Prof X hits a healthy G with all the guilt, fear and hope from the Skrull homeworld population and he just shrugs.

I think it had less to do with the poisoning and more to do with not having reconciled his life as a cosmic force of nature with his life as the mortal Galan, with the Xavier feat occurring after he had accepted his nature.

[Powerboy]

This is a stretch but in FF 243, Dr Strange confronted a weakened Galactus with all the souls he's ever consumed and it KO'd him. So if Galactus can be affected by something like that, it wouldn't be a cakewalk for Odin, right?

True but we've seen Galactus at extremely low power before and he was still a planet destroyer so that is literally the weakest showing we have ever seen from Galactus. Going with everyone at their high end, Odin simply no-sells the Penance Stare.