Overruled by whom? Austin is a city in Texas. Even if the City of Austin (being the people or the government of the city) wanted to do such a thing, the State of Texas would overrule it.
If the Texas GOP had any sense they’d impose upzoning on Austin from the state level. They can just say they’re giving Austin residents what they say they want. It’d be a win win for them.
That's what California did.
After Oregon passed HB2001.
I feel like Austin residents may be the worst of the worst—Californians who fled to Texas because they didn’t want to pay income taxes.
The GOP is against density from a political perspective though, not an ideological one.