Curious to see why you don't think it's happening? Do you think it's basically reverse Minnesota?Nah, Texas ain't flipping on presidential level.
I don't think it flips this cycle in particular unless Trump is convicted of felony before Election day (another discussion for another time), but I believe the ingredients are there for a future flip.
This is more of a nationwide phenomenon, same places that are seeing population growth are also seeing the biggest trends to the left, particularly in traditionally Republican suburbs and exurbs, which also traditionally gave Republicans such a big boost in elections. On the other hand, same places that are trending right are losing population, mainly rural areas, and don't affect the electoral margins as much. 2020's losses for GOP in Texas was blunted by the radical shift to the right in RGV, but the latter is less likely to be repeated than the former.