The Supreme Court disagrees with you.
The states have all the powers NOT DELEGATED to the federal government [please cite the express delegation of the federal government to prohibit secession], and the powers NOT PROHIBITED by the CONSTITUTION [not by congress, the President, or the Supreme Court - again cite where secession is prohibited].
Secession is not prohibited so long as it is done with the consent of a majority of the members of Congress.
Not true. You're just making it up as you go along.
Secession, ratification, and all other sovereign matters inuring to the People's power are flatly ultra vires the Congress of the United States and the United States court system.