Conceptually Fortress (if I understood it right) is like if you have a variable postgres_hosts looking like this:

    postgres_hosts['local'] = {host: localhost, user: 'abcd', password: DECRYPT_AES('defh'), dbname: 'base'}
    postgres_hosts['customer1'] = {host: prod1, user: 'saas_panel', password: DECRYPT_AES('pwdpanel'), dbname: 'base'}
    postgres_hosts['customer2'] = {host: prod2, user: 'saas_panel', password: DECRYPT_AES('pwdpanel'), dbname: 'base'}

    postgres_connection = connect(postgres_hosts[customer_id])

What Fortress does is maintaining that list of hosts for you:

    postgres_hosts = fetch('http://api.fortress.../{api_key}/postgres_hosts')

When you want to create a new customer in your system, you call fortress.create_tenant, and from their backend they will use your GCP/AWS credentials to create a new host and add it to the list (correct me if I'm wrong)

So in theory you could have only 'local' as a host in your .env.development file, and enable Fortress for production mode