Zend certified PHP/Magento developer

New to Magento phtml code doesn’t show

I’ve been trying to add phtml to my custom theme but it doesn’t show for example

<block class="MagentoCatalogBlockProductView" name="product_view_custom_block" before="-" template="Magento_Catalog::product/view/custom_block.phtml"/>

path for xml is <theme_name><theme>Magento_Cataloglayoutcatalog_category_view.xml

path is <theme_name><theme>Magento_Catalogproductviewcustom_block.phtml

the template="" what should I put inside the double quotes? Did I do this right?

I’m using Magento 2.4.4