However, I had installed to GCP using the Easy Install Script. So I’m not sure how to set that up. Would it be better to go into the container shell using docker exec -it command to set it up or is there a better way of doing what I’m looking to achieve.
You can also check your Domain provider panel, sometimes they do have an option to set up paid security certificates from there.
Regarding Lets Encrypt set up for self hosted ERPNext environment, it depends if you are using docker during installation or have done it without docker image.