Terms & Conditions checkbox remains untranslated

sounds similar to this one:
https://www.ads-software.com/support/topic/ive-read-and-accept-the-terms-conditions-only-in-default-language/

check you don’t have a theme customization that is providing that string on your checkout page (and not translating it), and if not, use loco translate to translate it.

polylang is only translating user-customizable strings, for standard strings that come with woocommerce you need the woocommerce translation files or override these with loco translate.
there’s a short explanation here:
https://github.com/hyyan/woo-poly-integration/wiki/Translation-Overview

Hi!
Thanks for the help! I’ve tried to do this as explained, but loco translate already had the right translation for the string, and it still doesn’t show up on the page. Any ideas what I could do now?
Thanks!

I also checked to see if the checkout.php was in my theme files (Divi), but there was none.

did you try switching to the storefront theme to rule out a theme problem?
did you try turning off other plugins?
Another plugin could hook this (I know this as I have done it myself, in this case the plugin would be using it’s own translateable string, or not.. )

Do note, this isn’t strictly within the scope of this plugin as is controlled by standard wordpress translation mechanism (the woocommerce .mo / .po files and any overrides provided by eg loco translate)

thanks for your quick reply. In the end it worked out well by inserting some css code.