I am as fed up as anyone with the overbearing, corrupt, secretive, and ideologically-driven actions of the Federal government, especially this administration. But breaking up the union is an existential issue that any administration, Democrat or Republican, would have to treat with the utmost seriousness.
BREXIT took advantage of Article 50 in the EU Treaty providing a means of withdrawing from the voluntary union. This article, which is standard for such treaties, was incorporated in the treaty from the beginning because the treaty is an agreement between sovereign nations, not political subdivisions within a single nation.
There is no similar clause in the U. S. Constitution.
To make an orderly and peaceful departure for Texas possible, you first have to pass a proposed amendment to the Constitution allowing such an action and get 37 states to approve it. Good luck with that.
Alternatively, the last time some Americans made a really, really serious effort to withdraw from the “indivisible” nation without such a clause, you may recall there was a civil war that killed 600K soldiers, wounded millions more, and savaged nearly half of the states comprising the nation at the time.