The paper assumes that 120k combat troops (a force equivalent to the troop buildup for the 2022 invasion) secretly assemble at the Polish border and attack in a flat featureless 2D space and then uses a 3rd party computer program for the results. It looks like a Master's thesis level of work designed to show the authors are able to do numerical analysis, which they seem to be able to do.
You'll notice it bears no relation to the real world where the professional Russian army is fully engaged in Ukraine, and the pre-invasion buildup was meticulously documented for months. Also, lmao at the assumption that Russia still has a functional airforce.