Okay, I will update you when I have news regarding the translation engine.
About the warnings you see, is the post saving correctly?
If it is, then these are probably warnings that were always there, just now that WP Debugging is activated they are displayed.
I suggest you disable the WP Debugging plugin, and if there is no visible error, meaning posts save fine, then it's probably okay.
For some reason your site's settings (on our end) only had Microsoft as a translation engine. We added the other two, DeepL and Google Translate, and they now appear on your site.
Please check and update me if anything is still missing.