Some Texas polls came out for Biden vs. Trump and they're not looking good. We're super early so polls aren't all that relevant but you cannot be a Republican incumbent and be within the margin of error for a state like Texas.

https://www.realclearpolitics.com/epolls/2020/president/tx/texas_trump_vs_biden-6818.html

Recent Quinnipiac poll has Trump 44, Biden 43; conducted 5/28 - 6/1.

Looks like people really don't like where things are with Trump right now and I imagine the George Floyd incident has a lot to do with it. His twitter feed was a bit more out of control than normal and there were advisors that urged Trump to deliver a unifying message from the oval office during the peak of the riots but he refused.

For reference, Romney vs. Obama polls had a RCP average of nearly 16 points: https://www.realclearpolitics.com/epolls/2012/president/tx/texas_romney_vs_obama-1945.html

The actual results for the state turned out to be just about spot on.