Article V states twice that only Congress can hold a Constitutional convention, not the states.
As the United States of America is both federal and national, passage and ratification must involve both Congress and the states. Article V states plainly that any amendment passed at a Constitutional Convention still has to be ratified by the states. This would make it redundant to hold the Convention at the state level. Both passage and ratification would happen at the state level. Neither would happen at the national level. Requiring ratification by the states asserts that only Congress could hold the Convention.
Article V also asserts that Congress would propose the mode of ratification ("as one or the other Mode of Ratification may be proposed by the Congress"). The proposal of a mode of ratification is part of the amendment proposal. Since the body that passes the amendment makes the amendment proposal, this says that any Constitutional Convention must be held by Congress . The states can’t hold a Constitutional Convention.
Another assertion in Article V:
A Constitutional Convention can’t vote on anything submitted, only on amendments generated in Convention. Article V requires submitting potential amendments to Congress, which may only vote on them in ordinary session.
Although Article V doesn’t express it, the two-thirds vote required for passage of a single amendment couldn’t logically be reduced for a Constitutional Convention. The difference between debating one topic in ordinary session and holding a Convention is scope: a Convention is unlimited in its power
to remake the Constitution.
It couldn’t require a smaller majority.
Constitutional Convention means the country is in desperate straits requiring total overhaul. It would mean deferring other business. This would be overkill now. We have had multiple amendments in play before without needing a convention.
It's never been more important that every American can separate myths about Article V amendment from facts, not to meditate on them but to defeat actions currently being attempted that rely on misinforming the public about the valid process. Experts disagree on some points but the important aspects aren’t actually in doubt.