Checkout error translations

Hello, I'm currently working on translations for the checkout on a project, I see all error fields come from php files and they have no translation available (the error string is hardcoded instead of having the __('') wrapper).

The problem is that the error messages I'm looking for are too many for just copying the file and try add the translation characters myself. For example, "firstname" is required. Enter and try again. Is hardcoded in multiple files.

The same happens for the other fields, and the generic error message: One or more input exceptions have occurred.

If I try to search the codebase, each php file has the strings just hardcoded in.