Yes, most public universities in Texas auto accept you if you were in the top 10% in a public Texas high school.
UT’s top x% varies by year (generally goes down), when I applied it was top 7%, now it’s 6 or 5.
That said, it only guarantees admission into the school, you might not get into your department — although if your department is liberal arts then you’re probably almost guaranteed that too. Given that, if you’re in engineering or something then you’re probably smart enough.