If you cannot get a TLS cert for internal infrastructure in a few minutes, I'd recommend you start looking into why.
still wonder how to do it in minutes.
Expect to spend 1-2 hours first time you try it until you can setup the correct DNS records, API keys and configuration.
Afterwards it's pretty hands off, every three months you'll receive an email from letsencrypt and you'll have to rerun this script to regenerate your certificates. Takes 2-3 minutes max (but of course you still need to distribute your certificates to all relevant services...)