1. Both doing this for saving their friends
2. Both had an agreement with their enemies (Kuma and Orochi)
3. Both stopping the others to do that instead them
There can be more, need the chapter.
Sure. They still mean different things though. That's just a list of the actions done but the meaning behind the actions is different
Zoro believed his dream is worthless if he let's Luffy die so his entire thing was built on what his dream means to him.
Oden here seems to be doing this because these are his men so he has to save them. That sort of thing.
Zoro does this where no one can see because he knows it's entirely about his own dream he's doing this so he doesn't have to get other people involved. This scene is so that the readers can tell Zoro's convictions are his own
Oden does this directly in front of everyone because it's a public execution. This scene was constructed to create sympathy from the Scabbards and people of Wano for Oden and the reader.
Theres different meanings behind similar actions.
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think you are forgetting that oden had not one ounce of compassion in him
What about him having a meal in merry of his dead friend? Or him taking the fall for Kin'emon with the Boar? Or him choosing to rehabilitate all of Kuri?
Don't you need compassion to do these things?