Best way to disable ngnix for good on Debian?

I have a Debian system running Zammad using the standard packages. Since I use Caddy as reverse proxy, I disabled nginx using systemctl disable. Unfortunately, everytime I update Zammad with apt update, the nginx service is enabled again and conflicts with Caddy. What would be the best way to disable nginx for good?

As a side note, the dependency between the application and the web server is unusual. Most applications just listen on a random port with HTTP after installation and lets the task of setting up a reverse proxy to the user.