Mitch wanted Kethledge first and Hardiman second.
Kethledge is supposed to be more of a moderate and Mitch thinks that would get him through easier than some. Hardiman has already been vetted so Mitch thinks he'd be an easier sale too.
Bottom line is that Mitch looks to be pushing what makes life easier for Mitch.
Frankly, Mitch McConnell, like him or not, knows what he's talking about. If Barrett, as he says, makes Murkowski and Collins uneasy, it would be unwise to pick her. This is a once-in-a-lifetime chance, and having the nominee fail and Democrats win control of the Senate in November is a scenario that has to be avoided at all cost. If the GOP wins seats in the Senate this November, then maybe you can go all-in on Ginsburg's replacement if she finally croaks.
Don't blame McConnell for Collins and Murkowski. It's not his fault he has to put up with them.