I’m too using Caddy with Let’s Encrypt on top of ROS but with Godaddy plugin, not Cloudflare, also custom build, similar to what @vovan700i described above. Work like a charm and I like it!
Note, if you use DNS verification plugin here, your Godaddy API token has a secret and a key, you just specify them both via semicolon:
tls {
dns godaddy YOUR_GODADDY_SECRET:YOUR_GODADDY_KEY
}