Of course @dimitarvp ,
I have a docker instance of rabbitmq management

sudo docker run --rm -it --hostname abdelghani -p 15672:15672 -p 5672:5672 rabbitmq:3-management

The elixir code looks like

mix.exs:
....
{:amqp, "~> 3.3"}
...
rabbitmq.ex:
def subscribe(queue) do
    {:ok, _connection, channel} = start_connection()
    :ok = declare_queue(channel, queue)
    :ok = consume(channel, queue)
    :ok
  end

  def publish(queue, payload) do
      :ok, connection, channel} = start_connection()
      :ok = declare_queue(channel, queue)
      :ok = produce(channel, queue, payload)
      :ok = close_connection(connection)
      :ok
  end

def start_connection() do
    {:ok, connection} = AMQP.Connection.open()
    {:ok, channel} = AMQP.Channel.open(connection)
    {:ok, connection, channel}
  end

  def declare_queue(channel, queue) do
    AMQP.Queue.declare(channel, queue)
    :ok
  end

  def consume(channel, queue) do
    AMQP.Basic.consume(channel, queue, nil, no_ack: true)
    :ok
  end

  def produce(channel, queue, payload) do
    AMQP.Basic.publish(channel, "", queue, payload)
    :ok
  end

  def close_connection(connection) do
    AMQP.Connection.close(connection)
    :ok
  end
end
consumer.ex
:ok = Rabbitmq.subscribe("index")
producer.ex
payload = ....
:ok = Rabbitmq.publish("index", payload)

I can check in web interface that each call for subscribe or publish results in process connection to Rabbitmq server and a new channel created, but the queues are empty and there is no coming data.