You have a typo. Its “acme_dns” not “dms”

This is really all you need to get started. Assuming you have built caddy with the cloudflare dns module

{
    acme_dns cloudflare cloudflare_api_key
    email your@email.com
}
pihole.yourdomain.com {
    reverse_proxy http://192.168.0.4/
}

Your cloudflare API key needs this: “API Token: Zone.Zone:Read and Zone.DNS:Edit permissions for the domain(s) you’re managing with Caddy”

One thing to mention, you probably want to configure the DNS settings on the caddy LXC to be something like 1.1.1.1 or 8.8.8.8 instead of pihole.

I really could care less what it looks like. It just needs to be functional/practicle

Nice, I happen to be on vacation this month. Should have lots of time to build the factory

No downside, it’s just there to incentivize people to buy the product. They give the impression of a “good deal”.