I followed the following setup in my staging/test server in web_only.yml. But it seems that the backups are still going in the latest discourse? Seems that it is ignoring the environment variable.
## Staging server specific settings
DISCOURSE_AUTOMATIC_BACKUPS_ENABLED: false
DISCOURSE_LOGIN_REQUIRED: true
DISCOURSE_DISABLE_EMAILS: 'yes'
DISCOURSE_S3_DISABLE_CLEANUP: true
DISCOURSE_ALLOW_RESTORE: true