Thanks for your time, shoen. Solved this one —
sudo certbot certonly --webroot -w /STORAGE/Sites/#####.#####.com -d #####.#####.com
sudo openssl pkcs12 -export -inkey “/etc/letsencrypt/live/#####.#####.com/privkey.pem” -in “/etc/letsencrypt/live/#####.#####.com/cert.pem” -certfile “/etc/letsencrypt/live/#####.#####.com/fullchain.pem” -out “/etc/letsencrypt/live/#####.#####.com/letsencrypt_sslcert.p12”
sudo security import “/etc/letsencrypt/live/#####.#####.com/letsencrypt_sslcert.p12” -f pkcs12 -k /Library/Keychains/System.keychain -T /Applications/Server.app/Contents/ServerRoot/System/Library/CoreServices/ServerManagerDaemon.bundle/Contents/MacOS/servermgrd