Seeing as AZ is considered a light red state, Sinema has a better chance of reelection in '24 than Kelly in '22.
Trump is less popular in Arizona right now than when he lost.
Arizona Republicans have no viable candidates who excite the Trump base.
Arizona republicans are engaged in high-profile infighting while Dems are united behind Kelly.
Republican leadership in Arizona trying to double-down on Trump's most decisive positions which risks shrinking an electorate that was already in the minority.
Demographic shifts in Arizona continue to favor Democrats.
Kelly at this moment sets up well for 2022.