I don’t have access to a Raspbian system at the moment. Can someone hitting this problem download https://raw.githubusercontent.com/certbot/certbot/v0.32.0/certbot-auto, make the script executable, and run it with the flags --no-self-upgrade --verbose and provide the full output?
EDIT: Changed GitHub link to raw script.
EDIT 2: You can skip this check because on closer inspection, it won’t verify what I want.
The problem here is Raspbian has configured pip to use third party mirrors which certbot-auto doesn’t trust. I’m not sure where Raspbian has done this, but configuring pip to not use piwheels.org would solve this problem.
With all that said though, OS packages are still the preferred way to install Certbot on this platform.