if i have to guess, the thing that prevents mobility now is constant surveillance, also by drones + lots of artillery, and some attack drones too. the thing that will enable large scale movements will be air dominance and even more EW
You also need an extremely well ran, integrated, well-trained, well-supplied army to run modern system warfare. Russia’s army is hardly modernised, and I suspect they wouldn’t be really willing to run a command model that gives a lot of authority to the lower ranks.