Hi Vladimir – I’m glad to hear you enjoyed the tutorial! Sorry for the delayed reply.
I’ve never used the Physical Atmosphere and Starlight addon but it seems like the calibration of Eevee volumetrics and/or the addon is imperfect. This has always been my impression of Eevee, especially volumetrics. Meaning that we have to play with the numbers and scene so it looks right artistically rather than expect the engine to deliver intuitive results. This is usually the case with non-physically-accurate render engines.
My advice is to use the addon primarily as the background visual. Then add a sun lamp to the scene to increase the illumination of the clouds until the energy matches visually with the background sky.
