I don’t know how to spell this out. Sinema is not ever going to be welcome to the Republican Party.
1) She started out as a Green candidate. (Yes, we know the Greens have acted as GOP shills in the past)
2) She is openly LGBTQ, which would not be welcome in the party.
3) She has always been vehemently pro-choice.
4) She has over the years taken numerous positions that put her at odds with the GOP.
5) Remember when Obama endorsed Sinema? (Good times...) You think that won’t be shown in Republican primary ads?
6) Remember when Sinema endorsed Biden?
The Rs may welcome Sinema temporarily as an Ind. caucusing, though her voting for McConnell would go against 90% of what she stands for. But it is impossible for her to survive an R primary. See what is happening to Oz in Pennsylvania, where the carpetbagging quack is meeting skepticism for his past liberal associations.
Sinema is NOT becoming a Republican.
Most likely, Sinema has a fantasy of running for President in 2024. Maybe she challenges Biden or Harris in the primary. Maybe she becomes a super high profile Green or Ind candidate guaranteed to Nader-ize the ‘24 election. But she’s not running for Senate again and she’s not joining the GOP.
Manchin, on the other hand, could become and Independent, decide who he wants to caucus with and possibly win re-election.