This will have tectonic effects in Asia. Basically all of the below red marked area starting with Lugansk and Kharkov (important historical city). Russia strategically speaking, cannot afford to see Ukraine in NATO. It is like having US bases along China border today in a unified Korea.
The water has crossed the limit; Even if Ukraine today declares that it won't joint NATO, Russians won't take any chances. They will strike through the black marked area with the aim to take the northeast & eastern provinces.
This is being coordinated closely with the Chinese; the CCP wants to make a quick land-grab and is desperate to demonstrate a show of force to re-assert its influence in China. There are enough faultlines now within the Communist Party that they are attempting to try this.
Capturing Taiwan in such a short window of time is not possible since Taiwanese terrain will require time and more manpower. The PLA will not want to trigger a WW3 over this.
But, it is enough time to grab huge chunks of land LAC and South China Sea territories simultaneously.
People, This has Cuban Missile Crisis 2.0 written all over it.