> Specifically I've very often wanted to do another git rebase -i in the middle of the first one, usually because I changed my mind about something and want to make changes to an earlier commit in my stack

I think this is what `git rebase --edit-todo` is for.

>Nah, it's wonderful. You see it as chaotic and jumpy because the conditions Git creates makes it feel chaotic and jumpy.

Fair enough. `jj` probably isn't right for me, but I'm happy it works well for you!