By the way, we've all been saying that, with Nacho and Lalo now out of the way, the only mystery left is the fate of Kim (and of Gene). But I think we're forgetting one other major character: Jimmy McGill.
It seems pretty clear that, in the BB universe, we're only seeing Saul, and any vestiges of Jimmy are gone. (Also worth pointing out that, in that one early-season episode where Gene gets locked in the stairwell, he scrawls "SG" on the wall, not "JM") But the character at this point in the BCS narrative does not seem capable of, for example, casually suggesting that Walt and Jesse murder Badger. Throughout the show, they keep nudging Jimmy down the road toward Saul, but then he pulls back. Even in this episode, his first thought when confronted with Lalo is to try to save Kim.
So what will ultimately "kill" Jimmy? Presumably, something involving Kim: her death, her leaving him, something like that. Whatever it is, I think the process for it happening will be fascinating to watch.