This appears to be something like 75% of their total operational power, with obvious, serious problems, like relying on civilian GPS, being evidently wholly unprepared for the mud, the fact that there's no comms chain back so they rely on Ukrainian comms networks staying up, the lack of a supply chain, the fact that the domestic population is finally catching on to the fact that Putin is illegally using his conscripts on the front line, the consequent astonishing rate of desertion from an army who weren't told they were invading until they crossed the border to "keep peace", the death of two generals, more aircraft losses than they expected, etc.
It's quite a big fraction of their power and what is very striking is that they appear unable to fully support it
The only people really surprised by this attack appear to be essentially all ranks of the Russian army -- an army spoiled by corruption and grift.
The bigger question is which ends first? The war, or Putin?