is there a way to create an incremental model without duplicates

I have data flowing into the source table every hour and I am looking to create an incremental model that consumes it and performs some aggregate. I have done this but I seem to be getting multiple entries whenever the incremental model runs instead of 1 aggregated entry

   {{ config(materialized='incremental')}}

WITH WEBSITE_MAIN_PAGE_VIEWS AS (
    SELECT
        DATE_TIME,
        POST_VISID_HIGH,
        POST_VISID_LOW,
        VISIT_NUM,
        VISIT_START_TIME_GMT,
        POST_PAGENAME,
        POST_EVENT_LIST,
        _DMLTIME

    FROM {{ ref('stg_adobe_hit_data_poc') }}
    WHERE
        1 = 1
        -- INCREMENTAL FILTER-----
        {% if is_incremental() %}
            AND _DMLTIME > (
                SELECT
                    COALESCE(
                        MAX(T._DMLTIME),
                        TO_TIMESTAMP_TZ('1900-01-01 00:00:00')
                    )
                FROM {{ this }} AS T
            )
        {% endif %}

)
    SELECT 
        'PO' AS BRAND,
        DATE(DATE_TIME) AS DATE,
        '*' AS BASE_MARKET,
        COUNT(DISTINCT CONCAT(POST_VISID_HIGH, POST_VISID_LOW, VISIT_NUM, VISIT_START_TIME_GMT)) AS TOTAL_WEBSITE_VISITS,
        COUNT(
            DISTINCT CASE
                WHEN POST_PAGENAME = 'po:en_gb'
                THEN CONCAT(POST_VISID_HIGH, POST_VISID_LOW, VISIT_NUM, VISIT_START_TIME_GMT)
            END
        ) AS HOME_PAGE_VISITS,
        MAX(_DMLTIME) AS _DMLTIME
    FROM WEBSITE_MAIN_PAGE_VIEWS
    GROUP BY DATE(DATE_TIME)

Here. is the sample of the output the code above is producing. if its not an incremental model it works fine as expected. but how do I convert this into an incremental model and it aggregates data as it arrives without any duplicate entry

I used this approach from this documentation and it worked for me

{{
    config(
        materialized='incremental',
        unique_key='date_day'
    )
}}

select
    date_trunc('day', event_at) as date_day,
    count(distinct user_id) as daily_active_users

from {{ ref('app_data_events') }}


{% if is_incremental() %}

  -- this filter will only be applied on an incremental run
  -- (uses >= to include records arriving later on the same day as the last run of this model)
  where date_day >= (select coalesce(max(date_day), '1900-01-01') from {{ this }})

{% endif %}

group by 1