3 options for caustics projection on the wall.
The BE WATER Lamp was used as a reference
https://www.waw-collection.com/portfolio/be-water-lamp/ 
! The lamp is not present in the scene!
The caustics are created in a fake way (does not slow down Corona, Vray rendering)
Wall size in the render: 4000(H)x3000.
Depth of the lower box = 138 mm (do not change its depth, otherwise the projection will be visible on the external plane).
To change the height of the projection – move the light source target.
Tone Mapping in the render: exposure = 0.5, Highlight Compression = 3 (change intensity according to your Tone Mapping settings)
To adjust the brightness intensity of the caustics, change the Multiplier in the light source, color is adjusted there as well.
For the fbx file, a screenshot with settings is included in the archive.

Attention! This method has a significant drawback: objects placed above the light source do not cast shadows.
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Format: Max2017+Fbx
Render: Corona v12 (LegacyMtl)

For Corona render, it is recommended to use a version no lower than 1.5, as the glossiness of the materials is set with PBR in mind.