Evidently Certbot is being executed by bash instead of Python.
Why I don’t know…
Can you post “head /usr/bin/certbot”?
Why are you creating a certbot-renewal service, though? One named certbot is already installed, isn’t it?
Edit: And what do “systemctl status certbot-renewal” and “systemctl cat certbot-renewal” show?
Edit: According to your previous post, you added /bin/bash to ExecStart. That is why you’re getting this error message.