How do I iterate through the nodes of /content and get the value of text property?

Question

below is my structure enter image description here

as of now I am using below code to get the value and set it to an element to write it into a xml document:

Iterator childPages = page.listChildren();

        while (childPages.hasNext()) {
            Page childPage = childPages.next();

            Iterator<Page> grandChildPages = childPage.listChildren();

            while (grandChildPages.hasNext()) {
                Page grandChildPage = grandChildPages.next();
                Element grandChildItem = document.createElement("item");
                channel.appendChild(grandChildItem);


                String textNodePath = grandChildPage.getPath() + RssConstants.CONTENT_SUBTITLE;
                Resource textNodeResource = resourceResolver.getResource(textNodePath);
                if (textNodeResource != null) {
                    ValueMap textNodeValueMap = textNodeResource.getValueMap();
                    String textNodeValue = textNodeValueMap.get("text", "");
                    Element subTitle = document.createElement("subTitle");
                    subTitle.appendChild(document.createTextNode(textNodeValue));
                    grandChildItem.appendChild(subTitle);
                }

               
                String grandChildNodePath = grandChildPage.getPath() + "/" + JcrConstants.JCR_CONTENT;
                Resource resource = resourceResolver.getResource(grandChildNodePath);
                ValueMap valueMap = resource.getValueMap();
                String grandChildTitle = valueMap.get("jcr:title", "");
                log.info("Grandchild Title: " + grandChildTitle);

        

            }
        }

I am directly passing the path in CONTENT_SUBTITLE which is not correct the container id may change while authoring. expecting to get this dynamically