Adding a .env file to reference password when running the '–admin-password' command – Docker

I am trying to set up the admin password for Portainer in the docker-compose file using a .env file. It creates the containers fine and according to the log it says the it "Created admin user with the given password". When I try to log in with the username ‘admin’ and the password which is hashed in the .env file, it says the password is wrong.

docker-compose

version: '3'

services:
  portainer:
    image: portainer/portainer-ce:latest
    container_name: portainer
    restart: always
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
      - portainer_data:/data portainer/portainer-ce
    ports:
      - 9000:9000
    command: --admin-password '${PORTAINER_PASSWORD}'

volumes:
  portainer_data:

.env

PORTAINER_PASSWORD='$$2y$05$q8...'

Alternatively, I have also tried the second method mentioned in the docs, which is storing the password in plaintext. That plaintext file is stored in the same directory as the yaml file. I end up getting the error "failed getting admin password file: could not get the contents of the file ‘./portainer_password’"

docker-compose

version: '3'

services:
  portainer:
    image: portainer/portainer-ce:latest
    container_name: portainer
    restart: always
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
      - portainer_data:/data portainer/portainer-ce
    ports:
      - 9000:9000
    command: --admin-password-file './portainer_password'

volumes:
  portainer_data:

portainer_password

123456

This issue has been confusing me and I have done a fair bit of Googling and reading docs, so I appreciate all the help I can get.