I think the MAGA Republican, because she'd be the only viable alternative for "McCain Republicans". Her approval rating among Democrats was already completely in the tank before she became an independent.
This would be true in a Midwestern state, but I would be stunned if 'McCain Republicans' weren't already a key part of the Hobbs/Kelly coalition; Lake very explicitly wanted them not to vote for her.
Exactly, a far-right nominee like Lamb would not win the McCain republican types anyway all Sinema's independent bid will do is win them instead of em going to Gallego.