This is a guide to deploying Nextcloud behind a Caddy reverse proxy, both running in Docker containers (an official Nextcloud one and a caddy-docker-proxy one), with the goal of implementing as much as possible via docker-compose files. This is much more difficult than it should be, for a variety of reasons:
As with Docker versions of software in general, documentation of the software does not always apply to the Docker versions, and the Docker documentation does not always include the Docker equivalent ways of doing things.
Docker images do not always expose the desired configuration knobs of the underlying software.
Nextcloud requires special configuration to run correctly behind a reverse proxy (and again, some of the instructions for this configuration requires modification for