Best guess given what we have seen. So based on road infrastructure break through to Tokmak and one has expanding operational options.  The greatest Russian military weakness of this war is manoeuvre.  They really suck at it.  They can drive but rapid manoeuvre to effect is not their strong point.  Their artillery and ISR are not set up for it and their C2 is badly built for it.  I would also bet money that their logistics can't support, especially with stuff constantly blowing up in