Hello,
Please always make the backup before the update, new plugins or any testing.
Check this how to update the theme:
https://xtemos.com/docs-topic/update-the-theme
You need to translate the parent theme only, but, please save the translation in the proper place:
wp-content/languages/themes/woodmart-pt_PT.po folder.
In this case, the translation would remain after updates and even if you delete the Loco plugin.
Best Regards.