Postgres password and user change in Plausible Analytics with Postgres:14-alpine docker image

Question

Is there a way to initially provide with custom db, user and password for postgres during installation. I am using self-hosted docker installation. If I try to give custom user and password, I get an error Password Authentication failed for user "postgres" even though I want to change my user which I provided with environment variable POSTGRES_USER. Why does db get created only with superuser postgres?

If I provide the DATABASE_URL=postgres://def:xyz@localhost:1234/database_name

example - server ip - 12.23.34.45

docker-compose.yaml -

plausible_db:

supported versions are 12, 13, and 14
image: postgres:14-alpine
    restart: always
    ports:

       1234 : 5432
    volumes:
       db-data:/var/lib/postgresql/data
    environment:
       POSTGRES_DB=abc
       POSTGRES_USER=def
       POSTGRES_PASSWORD=xyz
    plausible:
       image: plausible/analytics:v1.5
       restart: always
       command: sh -c "sleep 10 && /entrypoint.sh db createdb && /entrypoint.sh db migrate &&      /entrypoint.sh run"
    depends_on:

    plausible_db
    plausible_events_db
    mail
    ports:
        **** : ****
    env_file:
         plausible-conf.env
    volumes:
        db-data:
            driver: local
        event-data:
            driver: local

DATABASE_URL=postgres://def:xyz@12.23.34.45:1234/abc

Is it postgres://user:password@server-ip:port-mapped-to/$POSTGRES_DB ?

I get the following error -

Error - * (MatchError) no match of right hand side value: {:error, "connection not available and request was dropped from queue after 2000ms. This means requests are coming in and your connection pool cannot serve them fast enough. You can address this by:\n\n 1. Ensuring your database is available and that you can connect to it\n 2. Tracking down slow queries and making sure they are running fast enough\n 3. Increasing the pool_size (although this increases resource consumption)\n 4. Allowing requests to wait longer by increasing :queue_target and :queue_interval\n\nSee DBConnection.start_link/2 for more information\n"}

If provided with -

postgres://def:xyz@localhost:1234/$POSTGRES_DB

I get the following error -

Failed to connect: ** (DBConnection.ConnectionError) tcp connect (localhost:1234): connection refused - :econnrefused

Tried giving - postgres://user:password@server-ip:port-mapped-to/$POSTGRES_DB

image: postgres:14-alpine
restart: always
ports:
   1234 : 5432
volumes:
     db-data:/var/lib/postgresql/data
environment:
     POSTGRES_DB=abc
     POSTGRES_USER=def
     POSTGRES_PASSWORD=xyz