There are very many things happening in this un-provoked Russian invasion, and we can all take a guess according to our own outlook.
But rest assured one thing that absolutely is happening is the gathering and analysis of Russian military capabilities (or lack there of).
Russia cannot send its air force into the attack without revealing a great deal about its capabilities and also without the near certain loss/capture of Russian Air Force technology.
Putin sent poorly trained, poorly equipped conscripts instead to invade a nation he completely indeed estimated.