First we hear the Russian military is upset with Putin because he attacked, now it is because his attack wasn’t larger. We could obtain as accurate information from a Magic 8 Ball.
One of the biggest lies of Western media is that the attack on Ukraine was simply all Putin's fevered blood-lust
In fact, NATO is universally despised among Russian Government/Military. NATO expansion is recognized by the majority of Russians as a threat to Russia. Ukraine in NATO was considered a red-line for 20 years. Even the drunk Yeltsin, who the CIA helped elect, complained about it. The only difference is that then, there was nothing he or Russia could do about it.
Both appear to be true.
The military is of two minds.