I mean, what did Ajokli accomplish? Killing one Dunyain and then allowing Kellhus to be salted? Kellhus could've managed to get himself salted quite trivially without Ajokli's intervention. The Kellhus-betraying-Ajokli interpretation only works if Ajokli actually accomplished something AND THEN was tricked by Kellhus. Since this didn't happen, we're basically left with two options: 1)Kellhus fucked up and got salted, didn't plan for this possibility and is uber-fucked (though Ajokli still can't find him) OR 2)Kellhus fucked up and got salted but has a contingency plan and is hiding, which is why Ajokli can't find him.
I'm completely on board with this line of reasoning.
There is, though, one notable possibility. Kellhus needed Ajokli in the material world as some kind of tool (a spanner in the works, perhaps), but could only accomplish this by being possessed. From that point on he needed to end the possession, which was accomplished in the Golden Room. It's unclear that Kellhus actually wanted to defeat the Dunsult at that moment. Many of his statements seem to imply he actually wanted them to succeed, at least partially. Then it's conceivable he might use their success to his own end. Unlike devices of Tekne, which need to be scrutinized to gain understanding of them (as opposed to the Dunsult, Kellhus had no opportunity to do so), the No-God has metaphysical significance; Kellhus potentially could have surmised its nature and effect and planned for them.
The only thing that seems to contradict this theory is Kellhus's surprise when he sees Kelmomas in the Golden Room. But we can't really trust Kellhus. On the other hand, there were four other Dunyain there, who could have seen through his deception and work out his overarching plan from there.
All of this also doesn't mean Kellhus is on the side of humanity. As a Dunyain, it's very likely his goal is to master
his circumstances completely.
I do think Kellhus is not done for, but next time he appears, it would be in a diminished state. By design or by contingency, though, I cannot presently say.