Constitutional Convention is the primary path
Possible path is elect Governors and take over gop at the State level or create a new political party with express intention of repealing the 17th and 16th Amendments
Unless something is done, and quickly, to mitigate the flourishing Leftism amongst Millenials we won’t have time to get any of that done. In about a decade we will have reached a tipping point where enough of us have passed on to where they will outvote us.