Bezels like this are layers of finish. A base plastic sprayed with multiple layers of color and protective gloss/matte finish. Unfortunately removing a scratch on a soft surface like a plastic material like this, means abrading the area around the scratch down to that same level. Think of trying to erase a deep river bed from the landscape (like the grand canyon). You would have to bring the surrounding land down to the river bottom. And if you think of all those soil layers - that's just like the layers of finish on your matte bezel. The grinding abrasive cuts thru those finish layers so eventually the level of the scratch matches the surrounding area. But the resulting appearance is the finish layers are not visible as huge ugly rings of each layer.
Furniture repair people use waxy crayon-like material to fill in the scratches, attempting to match the color the best as possible. With random patterns like wood, that's much easier than trying to match the color/gloss of a solid surface. But such a waxy substance is at least removeable so you can experiment.