Thank you guys, all the merit for the fix goes to Pintea, aka Mihai Gosa; I only helped him with testing and remarks.
Mihai is one of the devs, and he is the one who dealt with shaders and environmental settings, so hopefully with his insight several other improvements are to be expected. He has always been very kind and helpful. Once he used to visit the forum regularly, and in a couple of occasions we had PM exchanges, but he doesn't work any longe for Ubi Romania and, despite his love for the game and for the subsim community that has not changed over time, now he rarely logs in here.
A big thanks goes to Jeff Groves too, who recently put me again in touch with him
