I just noticed that Texas only has 31 state Senators, which means that there are more constituents/residents in a state Senate district than a U.S. congressional district.
Just after the 2010 census reapportionment, Texas state Senate districts all represented 806,000 people.
So I looked into the Rio Grande Valley districts. I found one of them. It is Senate district 27.
Represented by Eddie Lucio jr. since 1991.
Its turns out he is the most conservative Democrat in the 31 member body. He is a major ally of far-right Texas Lt. Governor Dan Patrick. Patrick campaigns for his reelection!
He won a Democratic primary battle, in 2020, against a progressive, with 54%.
He is retiring now.
Hardly evidence that diminishes my description of the RGV as "conservative".
(But Biden did win 57.6% of the RGV vote while Trump got 41.6%)