Modify email message programatically

Hi,

I am trying to modify the email message for an email action via the ninja_forms_run_action_settings filter.

Here is my code:

add_filter('ninja_forms_run_action_settings', 'sg_download_nf_success_message', 11, 4);
function sg_download_nf_success_message($action_settings, $form_id, $action_id, $form_settings) {
	if($form_id == 1 && $action_id = 2) {
	$subject_message = get_field( 'subject_message', 'option' );
	$form_message = get_field( 'form_message', 'option' );
	$action_settings['email_subject'] = $subject_message;
	$action_settings['email_message'] = $form_message;
	}
	return $action_settings;
}

The problem is that this alters all messages and subjects for all my email action.
How can I target the ['email_subject'] and ['email_message'] for a specific action.

Or is there a way to add acf fields (from an option page) via the merge tags in the ninja forms interface?