I expect Phoenix to win best actor at the Oscar and even those that hated or didn't care for Joker movie will begrudgingly accept that Phoenix's performance in the movie was great if he wins.
But if Joker wins Best Picture or Phillips win Best Director then film Twitter will have a massive meltdown. They will claim that misogyny was reason the Little Women didn't win for Best picture. They already accusing the Academy Awards of sexism because Greta Gerwig didn't get nominated for best Director.
I don't think many people truly know or understand exactly how Oscar voting works, and how films get nominated. It's not like a small room full of stuffy old white men decide these things.
The Academy is comprised of nearly 8,000 members at this point (at least roughly 30% are women). Within the Academy, there are individual branches for each profession (actors, directors, sound mixers, etc). Here is a breakdown of voters from 1-2 years ago:
In the first round of voting, all members can initially vote on which films they would nominate for Best Picture, but then can only nominate for awards within their branch. For instance, Joaquin Phoenix could vote on which film he'd want to be nominated for Best Picture. Beyond that, he could only vote on nominations for Best Actor/Actress and Best Supporting Actor/Actress. Joaquin could not have even nominated Todd Phillips for Best Director.
After the nominations have been announced, the final phase of voting for winners allows all active and lifetime members to vote in any/all categories, although they are discouraged from voting in categories in which lack expertise.
Therefore, when it comes to nominations for something like Best Director, they are simply voted on by the several hundred directors in the Academy. I'm sure Greta Gerwig received some nomination support in terms of votes, but if she wasn't ultimately nominated for Best Director, it simply means she didn't receive as many nomination votes from her peers (other directors in the Academy) in comparison to the other directors in contention. People are always quick to pull the sexism card or blame things on Academy politics, but it's also possible (and very likely) that the majority of directors in the Academy simply didn't feel her work was a strong as that of other directors this past year. It likely doesn't have anything to do with the fact that she's a woman.
BTW, Greta Gerwig was nominated for Best Director in 2018 for Lady Bird, and Little Women was just nominated for Best Picture this year. As a young and talented director with a long career ahead of her, she already has a lot of support behind her and I imagine Greta is doing just fine...