Before 1850, Texas was a much larger state, owning much of modern day new Mexico and other territories? Texas gave this land to the federal government in exchange for debt relief. What if this never happened?
https://en.wikipedia.org/wiki/Compromise_of_1850
Texas is saddled with all of the debt incurred during their revolution and possessed more land than could be effectively enforced. Santa Fe was never forced under the control of Texas, though they did try multiple times. Most of the west was uncontrolled; only the core territory in the east was ever truly enforced.
Texas got a great deal; they exchanged land which was full of hostile Natives and hostile (New) Mexicans which paid off plenty of their debt.
I'm not sure of the
size of the debt incurred by Texas during the war, but it would certainly hamper its growth by quite a bit. You'd need to look in the incredibly long term, and it'd be likely that half of the state would be split off later, anyways.
Mind that this is the same deal taken by all of the other states that joined the union; they exchanged their extreme territorial claims for their debt to be paid off by the federal government.