One gotcha that I found is that Turbo does not define itself in the global scope when installed via webpack like Turbolinks used to do.
I have Stimulus controllers and SJR responses that used Turbo.visit(), and they all broke. I resorted to this in my application.js:
import { Turbo } from "@hotwired/turbo-rails"
window.Turbo = Turbo
Alternatively, I could have imported Turbo into each Stimulus controller that needed it. I wasn’t ready to rewrite my SJR responses yet, though.