Unfortunately that's one area I am bad with, I tend to use reverse_proxy for most such as Baikal running with the ckulka/baikal Docker image (which runs Nginx or Apache), otherwise I only static sites.

I'd start by looking at Baikal's config for Apache and Nginx, https://sabre.io/baikal/install/ and comparing to the directives for Caddy, https://caddyserver.com/docs/caddyfile/directives and

Since it uses PHP, it will need that, https://caddyserver.com/docs/caddyfile/patterns#php

Upon my searches I came across this, it talks about running Baikal with Caddy specifically. https://github.com/caddyserver/caddy/issues/497

I hope that this provided some helpful directions.

I use Caddy for this. I'll leave links to the documentation as well as a few examples.

Here's the documentation for wildcard certs. https://caddyserver.com/docs/automatic-https#wildcard-certificates

Here's how you add DNS providers to Caddy without Docker. https://caddy.community/t/how-to-use-dns-provider-modules-in-caddy-2/8148

Here's how you do it with Docker. https://github.com/docker-library/docs/tree/master/caddy#adding-custom-caddy-modules

Look for the DNS provider in this repository first. https://github.com/caddy-dns

Here's documentation about using environment variables. https://caddyserver.com/docs/caddyfile/concepts#environment-variables

Docker

A few examples of Dockerfiles. These will build Caddy with DNS support.

DuckDNS

FROM caddy:2-builder AS builder
RUN xcaddy build --with github.com/caddy-dns/duckdns

FROM caddy:2
COPY --from=builder /usr/bin/caddy /usr/bin/caddy

Cloudflare

FROM caddy:2-builder AS builder
RUN xcaddy build --with github.com/caddy-dns/cloudflare

FROM caddy:2
COPY --from=builder /usr/bin/caddy /usr/bin/caddy

Porkbun

FROM caddy:2-builder AS builder
RUN xcaddy build --with github.com/caddy-dns/porkbun

FROM caddy:2
COPY --from=builder /usr/bin/caddy /usr/bin/caddy

Configure DNS provider

This is what to add the the Caddyfile, I've used these in the examples that follow this section. You can look at the repository for the DNS provider to see how to configure it for example.

DuckDNS

https://github.com/caddy-dns/cloudflare?tab=readme-ov-file#caddyfile-examples

tls {
	dns duckdns {env.DUCKDNS_API_TOKEN}
}

CloudFlare

https://github.com/caddy-dns/cloudflare?tab=readme-ov-file#caddyfile-examples Dual-key

tls {
	dns cloudflare {
		zone_token {env.CF_ZONE_TOKEN}
		api_token {env.CF_API_TOKEN}
	}
}

Single-key

tls {
	dns cloudflare {env.CF_API_TOKEN}
}

PorkBun

https://github.com/caddy-dns/porkbun?tab=readme-ov-file#config-examples Global

{
        acme_dns porkbun {
                api_key {env.PORKBUN_API_KEY}
                api_secret_key {env.PORKBUN_API_SECRET_KEY}
        }
}

or per site

tls {
	dns porkbun {
			api_key {env.PORKBUN_API_KEY}
			api_secret_key {env.PORKBUN_API_SECRET_KEY}
	}
}

Caddyfile

And finally the Caddyfile examples.

DuckDNS

Here's how you do it with DuckDNS.

*.example.org {
        tls {
                dns duckdns {$DUCKDNS_TOKEN}
        }

        @hass host home-assistant.example.org
        handle @hass {
                reverse_proxy home-assistant:8123
        }
}

Also you can use environment variables like this.

*.{$DOMAIN} {
        tls {
                dns duckdns {$DUCKDNS_TOKEN}
        }

        @hass host home-assistant.{$DOMAIN}
        handle @hass {
                reverse_proxy home-assistant:8123
        }
}

CloudFlare

*.{$DOMAIN} {
        tls {
	        dns cloudflare {env.CF_API_TOKEN}
        }

        @hass host home-assistant.{$DOMAIN}
        handle @hass {
                reverse_proxy home-assistant:8123
        }
}

Porkbun

*.{$DOMAIN} {
        tls {
	        dns porkbun {
			api_key {env.PORKBUN_API_KEY}
			api_secret_key {env.PORKBUN_API_SECRET_KEY}
	        }
        }

        @hass host home-assistant.{$DOMAIN}
        handle @hass {
                reverse_proxy home-assistant:8123
        }
}