The two words mean the same thing.
States did not surrender their sovereignty. They only delegated certain powers. Read the federalist papers. Specifically #46 though several others say the same thing. I am quoting Madison and Hamilton - the Constitution’s two biggest proponents when I use the term delegate and “limited powers” and describe the states as sovereign.
The states collectively are not the federal government. It is an entirely different entity.
States can leave if they wish. The union is voluntary and based on consent. That’s how it was founded. Might does not make right.
Trying to rely on Texas V White to support your argument is a joke. Did anybody expect them to rule against the federal government after it had just fought a bloody war? The justices of the court would not have survived 24 hours if they had ruled that way....never mind that Chief Justice Salmon P Chase issued the ruling that the then treasury secretary was entirely in the right......a certain Salmon P Chase. Yes! Look it up if you doubt it. This was just an ex pist facto “might makes right” attempt at justifying the unconstitutional war they had already started and fought at great cost.
You are apparently big on oppression and tyranny.
And yet it stands as settled law (unless of course you would like to mount a legal challenge to it). States enter the union via congress and must leave the same way.
The confeds tried it the other way and learned they warn’t might or right!