Principle residence is where you actually live most of the time. It can be different than your "domicile" depending on the facts and circumstances.
However, I would say you have been domiciled in Texas since 2016. Again, it's a combination of all facts and circumstances, and the fact that you sold your FL home, never returned to FL, and changed your doctor and other important relationships, establishes a Tx domicile more than failing to change your drivers license or voting.
