Texas can become 5 states with 10 senators.
https://www.dmagazine.com/publications/d-magazine/2009/july/the-five-states-of-texas/
yes indeed, Texas 1,2,3,4,5!
From the Texas State Library and Archives Commission (https://www.tsl.texas.gov/exhibits/annexation/part5/question7.html):
“The power to create new states could be exercised only by Congress, with the consent of the affected state legislatures. “
And importantly:
“In 1850, Southerners wanted to exercise the provision to create another slave state from Texas to balance the admission of California as a free state. In one of the provisions of the Compromise of 1850, Texas was instead given a payout of $10 million to give up its northern and western claims. A few years later, the Kansas-Nebraska Act repealed the Missouri Compromise and made the issue of the boundaries a moot point.”
“Although in theory Texas could still be divided into multiple states, ANY possibility of carving additional states from Texas ENDED when the Civil War settled the question of slavery once and for all.”