Imho Putin would never have invaded unless he believed he could overthrow the existing government.
I don’t know the details on what basis he came to that conclusion, but I would very surprised if it turned out to be an error.
If Putin was so brilliant he wouldn’t be resorting to violence now. He’s a thug who knows nothing else. He’s met his Waterloo. Ukraine is the size of Texas and has 40 million people. That is not a nation conquered by conscripts and Soviet era equipment.