Remember the glory days of the Disney Renaissance? One thing we regularly saw then was Disney's animated features getting multiple Oscar nominations for best song. Twice (Beauty and the Beast  and The Lion King ), they racked up three nominations!
Let's use The Lion King's feat for our discussion as it's the clearest example of what I have in mind.
"Can You Feel the Love Tonight" was the big winner. We all knew that would be the case. The big love ballad. The song resung by a popstar over the closing credits. The big radio hit. It was going to win.
But in my opinion, it should not have. The win should have gone to "Circle of Life" which was the thematic core of the film (and, in my opinion, the superior song). My thinking is that voting should be biased in favor of songs that engage the entire movie, that pull it together, that are the engine for its plot and/or the explanation of its characters and/or explicative of the film's ultimate message. Not the one that Elton John got on the radio.
(I've been annoyed by this Oscar for thirty years.)
Anyway, these coming Oscars seem to have the best shot at a three-nominee in ages with Barbie. I think the likely nods are, in order of appearance, Lizzo's waking up song, "I'm Just Ken," and the Billie Eilish number.gone to number one and so that seems, according to 90s rules, the likely winner. I genuinely don't know if those rules still apply, however.
I do think her song is a strong candidate by my rules also. It first appears at arguably the emotional climax of the film and helps make that moment really work. At that time it, again arguably, clarifies the thematic purpose of the film. And then we get to hear it (I think the same version?) over the closing credits. So it's checking both boxes.
But I'd encourage you not to sleep on Lizzo's "Pink" which is genuinely funny and is reinvented when reprised to show how Barbie's reality is changing underneath her. It's doing interesting things.
I can only guess as to the Academy's motivation as to what happened next, but I'm assuming they felt those movies both should have won (what they lost to: Dreamgirls, Enchanted) but their vote was too split. I'm not sure that's true, though. Sure, the songs Enchanted were what "should" have won during the Nineties when Disney dominated, but, I mean, don't you think that Once song is more deserving? I do.
Anyway, the Academy was unhappy and made a new rule: a movie can only earn two Original Song nominations. So we'll never know if a third would otherwise have qualified.
I'm interested to see how Warner Bros pushed Original Song when it's for-your-consideration time. My guess is Billie and Ryan will get the push. And that's fine.