Also other than 2012-2016 Texas hasn't trended that D in one cycle
2000: 22 points more Republican than the Nation as a whole
2004: 21 Points more Republican than the Nation as a whole
2008: 19 Points more Republican than the Nation as a whole
2012: 20 points more Republican than the nation as a whole
2016: 11 points more Republican than the nation as a whole
2020 : 10 points more Republican than the nation as a whole
Linear trendline is 2 points every 3 years:
https://www.desmos.com/calculator/znz4z8ukw2(tiny bit less if outlier 2012 is included, more if included)
That would mean 9 more years needed under the observation that the US is structurally a Dem+4 country in normal presidential years.
2034 here we come.