In Article 1, Section 3 of the Constitution, it clearly lays out that it is a State’s (legislature) right to select and appoint senators therefore representing said state. Regardless of what Congress had passed in the 17th Amendment, that right explicitly belongs to the individual states and, even though was agreed upon in 1913, the states should continue in ownership of said constitutional right and be able to rescind said transfer of rights to the election of senators.
This should be brought before the US Supreme Court by a coalition of states to take back what rightfully belongs to the states. In the argument before the Supreme Court, the states should also address the issue of Congress making any amendments regarding Constitutional rights, either belonging to the States or the Citizens, where they have only interest in removing said rights from their constitutionally respective owners.
The benefit of each state’s legislature vetting candidates for the US Senate is that each senator will more closely represent the political makeup of said state and not be decided on by political campaign funding and deceptive advertising practices. The state legislatures will be able to find the best candidates to fully represent the interest of their state.