The only similarity is they are both swordsmen. Oden is much more similar to Luffy in his attitudes and beliefs. He wants to be free, has kings haki and Voice of all things. The similarity with Zoro is superficial.
Well parallels don't fall down to just personalities
Ryuma’s personality is vastly different from Zoro's if you read monsters and even his zombie version has a different personality from Zoro... But you can't say there's no parallels between them right?
Same with Rayleigh and Zoro, vastly different personality wise but there's to her things making parallels between them
Parallels can range from fighting style to feats to plot progression to character progression to physical appearance to even just items passing between characters
Luffy's strawhat passes from Roger to Shanks to him and that alone can create a parallel among other things between all three characters... Same way Ryuma's sword passing to Zoro and Oden's sword passing to Zoro does
And of couse among all the other things I listed in this thread... These things can only be considered superficial if they carry no thematic relevance but that's not true