I posted a guide on taking the Pi-hole Chronometer output (pihole -c) and displaying it inside a web page. That involved extracting the output into a text file, repeating this every minute by cron to keep it updated, and then using Pi-hole's own web server to display it with a refresh tag to read the updated file once a minute.
A bit hacky but it worked. It's not really what you're after but I mention it in case there's anything useful in there you can use in your application.