Hi,
Thanks for the details. You need to use hook hivepress/v1/templates/listing_edit_block to add any custom content without overwriting the entire template. You can view examples at this link. Also, please see the example of how this is done in Paid Listings: hivepress-paid-listings/includes/components/class-listing-package.php at master · hivepress/hivepress-paid-listings · GitHub.
I hope it helps