I expected he'd have multiple residences all over the world including in half a dozen (at least) US states so he'd have to have a residence or two in Texas. So as much as he "lives" in any one place, Texas would be one of the places he lives.
I don't think Elon Musk actually does live in Texas. He lives in Los Angeles. I know he said he moved to Texas but I haven't found any sources that could verify that he actually has moved or where he supposedly moved to.
Elon moved to Texas for various reasons. 1: SpaceX's new vehicle, known as the Starship, probably for testing. 2: Tesla is building their Gigafactory in Austin. 3: There is no personal income tax in Texas.
"Texas was an independent country" is debatable and should maybe be removed/changed to "de facto independent". At the time it didn't have much international recognition (only 3 countries in Europe) and I imagine if you read a Mexican history textbook it would say Texas was part of Mexico.
https://www.jetpunk.com/quizzes/presidents-by-state-quiz
Maybe you can in five years