Omni - a standard light source 3ds Max. The analogue VrayLight Sphere.
In omni, always, by default, off the shading and light attenuation. That is why, he Relight scene, bleached shadows.
Adaptive DMC, is a method of anti-aliasing , other than Adaptive subdivision, of course, renders received one method will differ from renderings obtained otherwise.
More particularly, the Adaptive DMC provides a sharp image, its artifacts resemble a rash gray shadow. Adaptive subdivision, on the contrary, gives a blurred image, its artifacts similar to dirt or wool.
How to remove the cotton wool to render , read our tutorial about Choice GI engines in V-Ray😉