So took another apporach – Anti-join

{% if is_incremental() %}
        left join {{ this }}
            on orders.request_id = {{ this }}.request_id
                and orders.__metadata_timestamp = {{ this }}.__metadata_timestamp

    where {{ this }}.request_id is null
{% endif %} 

But unfortunately EXPLAIN plan revealed Redshift performs anti-join + filtering after performing 2 GEO-spatial joins.
Which technically means processing full data set and resets any incrementality benefits.