Map of the Great Meteor, a Sea Mountain with ~4000m high, nearby the Azores Island. The Layout template is from the Layout Loader Plugin

The major exercise of this map was the ability to put bathymetic contours labels following a line from an helper layer called labels, instead of randomly place along the contours.

This was the expression used on the labels placement geometry generator.

coalesce(
aggregate(
    'labels', -- layer
    'collect', -- aggregate type
    intersection(
        buffer($geometry,3000),
        geometry(@parent)
    ), -- Expression
    intersects(
        $geometry,
        geometry(@parent)
    ) -- Filter
),
$geometry
)

Data: GEBCO (https://www.gebco.net/data_and_products/gridded_bathymetry_data/)