[Закрытые] Theme level string translations

I'd like to translate certain text at the theme level such as 'Related Issues' and 'Related Content' on a page like pr-1970-affiliate-website-platform.pantheonsite.io/es/know-your-rights/language-access-is-voter-access/. I followed скрытая ссылка
but interested to do this via code because I have numerous sites using the same theme. Could you provide details on how this can be accomplished? I looked into this thread wordpress.stackexchange.com/questions/127917/generating-po-mo-translating-files-from-scratch-in-a-wordpress-theme/320250#320250 but not sure if I should follow this approach.