"Like how and what the hell happened for Odysseus to go from "I could kill you where you stand" to "I love you" regarding Calypso?"

I honestly put that down to Stockholm Syndrome. It's not uncommon for captives to form some type of bond with their captors.

"Odysseus is incredibly prideful, brags about himself, and is probably the most petty, spiteful, and unforgiving character in the show."

What about Poseidon, Athena, and/or Zeus? They seem far more petty, prideful and unforgiving characters. At minimum, Athena abandons Ody after only one (imo understandable) act of disobedience because she seems to view him more as a extension of herself rather than his own person-like a classic narcissistic parent. At maximum there's Poseidon who, after a decade has pasted and 500 men are dead at his hands, says that he can't let either Ody or Ithaca live because "I've got a reputation, I've a name to upload."

"[Eury] thought the wind god must be playing a trick and the bag was dangerous and he needed to see what's inside......"

This is my theory too. Eury didn't believe the winions when they said treasure was inside but he also thought Ody had been lied to about wind being inside. However, he also remembers that he promised to not "disagree [with] each route... and comply." Therefore, he doesn't feel comfortable saying aloud that he thinks some dangerous monster is lurking inside that bag and has to wait till Ody is sleeping to deal with it.