Do you think Gerwig and Robbie are secretly furious they didn't get Oscar nom'd (yet Gosling did)

They did get Oscar nominations, just in different categories. I seriously doubt they are mad they didn't get nominated for director and actress.

I doubt it. They're both keenly aware of how their industry works and which types of films tend to get nominated for which types of awards. I doubt it was even a surprise to them that they weren't nominated for best director and best actress in a leading role respectively. They've both been nominated before for films that are more Oscar-y. And I suspect they may both be nominated again for films that are more Oscar-y.

The 'snub' stuff came from Gosling supporting his colleagues and lots of quite dim people on the internet.

I'd imagine they're both still basking in the glow of the film's financial success and cultural imprint and probably not concerning themselves too much about award nominations.

I doubt they're furious. They might be disappointed they didn't get director/actor nominations, but I don't think it'd be that much of a problem for them.

Think about it this way: their movie made bank at the box office, got huge buzz, got nominated for a BUNCH of other awards, and was a success all-around. It'd be hard to generate fury when you're sitting on top like that.

They're far more angry that Gosling didn't stuff the beef between their respective buns during the shoot

No as I'm sure they made a ton of money and deep down they knew the movie wasn't Oscarworthy. Also both ladies will have have a ton of opportunity based off the success of Barbie. Gosling only got an Oscar nomination as he was the only real actor in the movie and gave depth to a character written as a brain dead idiot.