And I’m seeing you don’t recommend anymore WPML. I love that Sage it’s very opinionated, and I would like to know which plugin (or alternative) do you recommend now to manage translations.
Also there is a lot of debate over performance of localization plugins, but no real independent test.
I’ll update the book because that docs page was indeed removed recently. I’ve made a note to create a top-level page outside of the docs where we can maintain a list of plugins/tools we recommend using, since this wasn’t really specific to Sage
As far as WPML alternatives go, Polylang and Multilingual Press both seem to be well regarded.