This has been answered by Zapier Support already with proposed solution to use Translate by Zapier (which works as an intermediate solution), but that requires an extra step which I think is unnecessary since Zapier’s datetime formatting library already has this built-in. Therefore this thread serves as an official feature request to Zapier’s developers to offer output locale support in Zapier’s datetime formatter.
I'm having a hard time finding information about localised (long) day and month names. I've searched the community forum and all various help articles, but none mention anything if the formatted date result is localised -- or info on how to make them localised. I did find your Intl.DateFormat library on Github, where there is a output locale parameter, but this seems unsupported in Zapier itself. Could you please know how to get a localised French date like Janvier, Lundi 3, 2023.
locale - A BCP 47 tag to identify the output languageType: stringDefault: The system localeExample: fr, fr-FR