Hi there,
Are you using the popular WPML plugin by any chance?
If so, I wouldn't overthink it too much; the necessary hreflang implementation will be automatically added to each variation of the page providing you "link them together".
If you are a smallish operation and don't have a staging side to play around with, then you can prep all of these posts ahead of time and simply save them as drafts
My only recommendation would be to make sure nothing is published prematurely; it's better to wait and translate rather than adding placeholder /lanuage/ versions with little or zero content.
I'd also look to set up different language version folders within Google Search Console to ensure everything is indexed properly, geotargetting is enabled and that your foreign language ones ARE receiving traffic and clicks from Google.
Here's some further reading:
Google Search Console setup for href lang - https://support.google.com/webmasters/answer/182192?hl=en
Official WPML guide with good visuals - https://wpml.org/documentation/getting-started-guide/
Moz Href lang/international guide - https://moz.com/learn/seo/hreflang-tag
Good luck with the implementation, if you've made it this far with WordPress you should definitely be able to make the plugin work