Exaggerate the overview area in the map composer

Question

I work with QGIS 3.28. As part of an atlas, I have a main map object map 1 and a small map object map 2 (small scale) for location. The layer used for the atlas iteration is a polygon layer. The footprints/areas of my polygon layer vary greatly from one another. In the properties of the map 2 object, I activate the overview pointing to map 1 in order to display the extent/spatial footprint of my map 1 on this map 2. The concern is that the extent of my map 1 being variable (scale not fixed), for my polygon layer which have small spatial footprints (map 1 very zoomed-large scale), the spatial footprint of my map 1 is no longer visible on my map 2 What would be the solution to always make this overview of my map 1 visible on this map 2? Is there a way to exaggerate the extent of map 1 in the overview?

If not, I had thought of the style/geometry generator solution on my atlas iteration layer (for example, an expression that would generate a centroid and a 500m buffer from the polygons?). Are there any other solutions?

Below a screenshot. Left: no problem, the overview allows seeing the map 1 extent. Right: the scale is too high, and the overview does not succeed in displaying the map 1 extent.

Answer 1

I reply to my question. In the 'overview' section, select the color corresponding to the 'frame style' (a left click allows you to enter the symbol parameters). Select 'single fill' then in the symbol type, select 'centroid fill'. You can then enlarge your point and put some transparency.