Incorrect.
It must be ratified by 3/4 of the states. Currently 38 states are required.
Nope, the US Senate isn’t an amendment. It’s in the Constitution itself. It requires 50 states.
Actually the Senate (or rather the equal representation of each state in the Senate cannot be altered by a Constitutional Amendmentit’s specifically mentioned in Article V which deals with amendments. All (that would be 50) of the states would have to agree to it. Practically speaking the only way of getting rid of the Senate is getting rid of the Constitution itself.
Of course that might be what they really want. The Constitution, written by dead white men, has all of those outdated ideas like God-given rights, the electoral college, the 2nd Amendment just seems to get in the way of “progress”.
Wrong.
The Amendment power does not extend to abolishing the Senate. That is forbidden by Article V.