Pair machine translation with human, vetted translation in a way that's transparent to the viewer

[somewhere i wrote about this, can’t find it right now, this will just be building a first take at a solution]

$link['fragment'] = "googtrans(en|$lang)";

https://api.drupal.org/api/drupal/core!lib!Drupal!Core!Menu!menu.api.php/function/hook_link_alter/8.9.x

For our current approach, see https://www.drupal.org/project/cyborgtranslate

By making this simple module we successfully adopted a hybrid approach, whereby if Cambridge commits to translating elements of the site via Drupal’s built-in language interface, we can exempt those sections from Google translation.

To have a section which is not translated, because you have fully taken care of it through Drupal’s interface translation, or content translation, put class="notranslate" on the div, span, or other element surrounding that section.