joaquimP-2

Problem:
How to correctly convert my translation from using WP editor to ATE
Solution:
You would have to copy them one by one manually to insure a complete transition,

And keep in mind that you should never update/edit the translations using the page editor in second language, else, your translations will be lost.

Always use one method to translate and edit translations, in your case, I recommend sending the page for translation and edit it from ATE.
Relevant Documentation:
https://wpml.org/documentation/translating-your-contents/translation-editor-options/

Problem:
How to use Yoast SEO with WPML - Title is too long in translation
Solution:
The green line underneath the SEO title turns red when your title is too long. So keep an eye on that, and use the feedback to create great headlines, and do not make page titles translations too long so that it won't happen in the other languages.

I was able to get that information from Yoast SEO official website : https://yoast.com/page-titles-seo/
Relevant Documentation:
https://wpml.org/documentation/plugins-compatibility/using-wordpress-seo-with-wpml/