Republicans would need control of at least 34 state legislatures to be able to call such a convention, and 37 to ratify any amendments.
So far they have unified control of 31 state legislatures. Of those 31, 19 have signed onto an application for an Article V Convention put forward by Convention of States, a conservative activist group.
https://www.businessinsider.com/constitutional-convention-conservative-scholar-states-2022-8
https://www.businessinsider.com/constitutional-convention-conservatives-republicans-constitution-supreme-court-2022-7
I don't think anyone would have predicted the DNC abandoning all state level parties back a decade ago, but it happened.
The plan to call a constitutional convention by gaining control over state legislatures has been a plan decades in the making by Right Wing Billionaires. Nancy MacLean wrote about it in Democracy in Chains. Fascinating read.
Democracy in Chains: The Deep History of the Radical Right's Stealth Plan for America