I don’t think we’ll see Kim again, there’s a pretty big time jump that’s happened, we’re now in the breaking bad timeline.
You say that but,
The timeline jumps all over the damn place. I expect that the next episode will start out as though that last scene never aired. It’s a seed.
I think the last episode illustrates that Kim leaving is the final step in Jimmy completely becoming Saul.
But there’s a gap, and a few more episodes to go.
I think the entire point of this show is bugger all to do with the titular character, rather it’s documenting Kim’s fall from grace (mirroring BB). The “final step” for Jimmy given that Kim isn’t in Breaking Bad surely has to be her death.
What I’m not quite sure of is where the Gene (Cinnabon) arc fits in.