Do you know how the 'Related Issues' and 'Related Content' text is added to the page? Are you able to locate this with your current theme files? If so, could you please share the relevant code?
To make your text translatable, you need to wrap all static texts in gettext calls (e.g., __(), _e(), etc.). After that, go to WPML → Theme and plugins localization and scan your child theme for new strings. This will register them in WPML’s String Translation, where you can provide translations.
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Adding GetText Calls to PHP Code
In PHP, wrap all the hard-coded strings in gettext WordPress localization functions like __() and _e(). Specify a text domain to uniquely identify translations for your theme or plugin.
The __() function returns the strings
__('Hello, world!', 'your-text-domain');
The _e() function echoes a translatable string
_e('Hello, world!', 'your-text-domain');
These functions find the correct translation in the specified locale and domain. If no translation is available, the original string will remain unchanged.