Back in the early days of Drupal 8 there were a number of competing composer projects aimed at standing up a Drupal site from a simple composer command on the CLI. The one I settled on was one of the more active at the time. However, it was not the one that was ultimately adopted by the community.

Drupal has pretty good multilingual support out of the box. It's also fairly easy to create new entities and just add translation support through the annotation. These things are well documented elsewhere and a quick search will reveal how to do that. That is not what this post is about. This post is about the UX around selecting which fields are translatable.