Conceivably 2028 under a big Democratic victory, don't think thats very likely though
This is where I'm leaning. My current thinking is that 2028 will probably be the fallout of a second Trump administration with a more articulate and inspiring Democrat like Ruben Gallego at the helm, so it would almost be a fluke. But absent that, Texas becomes a swing state- never totally blue, Republicans would probably change their platform before conceding that many electoral votes- later on in the 2030s.
I believe DeSantis will be president in 2028 and easily hold onto Texas in his re-election bid.