It's hard...but so were the Georgia runoffs.

Mark Kelly also wouldn't have beat Martha McSally if he didn't already possess the skill to read/relate to Arizona voters -- no matter who he was married to! Such a Democrat would obviously have to defeat Sinema in a primary, first...which would suggest that she/he is an extremely dynamic hypothetical challenger in the first place.

I do think the more likely scenario is that Sinema comes to her senses and negotiates plenty of goodies for Arizonans, after making a big performative show over how she (and Manchin) tried to "bring in" reasonable Republicans, but, since none of them would budge, so she was forced to "put Arizona first."