It should be made clear to Collins if she votes no, there will be no money from the RNC or the Senate campaign fund. In addition, the money will go to whoever challenges her in the primaries.
Collins in Maine as a Republican is tenuous. I think McConnell knows she is close. Strangely, if she votes “NO” and McConnell punishes her, that may help to burnish her “independent” bona fides with her voters and help her to possibly prevail in her next election. There is no telling what will happen.