Sinema is even more stubborn than Manchin. She's the "I don't give a f*ck what other people say or think" type of politician - she's also said as much.
I just think her situation there in AZ much different than Manchin in WV
as you said, he the best Dems will get out of that state, while dems have options in AZ
she going to be the sole vote to get in the way of Dems’ overarching political agenda (for which ending/adjusting filibuster is truly required for that, which I think it is)? if she wants to end her political career, OK....but otherwise she can get the fukk out of the way
 it sounds like there may be some confirmation bias here...
 - and the other is that he knows damn well if Congress can't keep delivering / the 50 Dem Senators are threatened by illness, accidents or what have you, it could spell a midterm loss that will stall 2 or more years of major things he's trying to accomplish in his presidency. Biden and his people are clever enough to spin an image to the media and may just be savage enough to play realpolitik in their actions. Which will anger and terrify the GQP, and I'm completely here for 
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