WHAT PROBLEMS COULD COME TO SPANISH TEXAS NOW THAT THE USA IS NOW OUR NEIGHBOR?

The main problem is that Spanish Texas was sorrounded by a fast-growing and fast-developing country to the North and East: the United States.

Explanation:

While Spanish Texas was very sparsely populated, and did not attract enough settlers to drive the Native Americans away from the territory, or to build a well-functioning economy, the United States was receiving new settlers every year, who were pushing farther and farther west, to the point that they were starting to settle in Spanish Texas.

that is probably something for you to answer