With all due respect to your view, that looks to be backwards.
If Manchin runs for reelection as a dem, he doesn't have much chance at getting reelected against an R; on the other hand if he flips to R, he beats anything the Dems have on the bench.
Manchin has been wining elections as a Democrat in a Red state since 2004.
...on the other hand if he flips to R, he beats anything the Dems have on the bench.
If he switches to R then he won't survive the primary challenges in 2024.