Here's my prediction:
Russia is basically an abusive ex husband abusing his ex for flirting with other men.
I think Russia will annex the eastern part of Ukraine where there is probably some support within Ukraine itself, without threatening the rest of Ukraine, which would provoke probably far more intense opposition.
NATO and the west can then be furious about it, but if Russia stops in eastern Ukraine they will claim some victory in stopping Putin, whilst Putin claims victory in invading Ukraine.
All the while, Europe, and especially Germany, gets it’s Russian gas, which given they have supplied Ukraine with no support would suggest it is their greatest concern (Ukraine has always been a pawn between two greater powers, much like Poland, Belarus etc)
So eastern Ukraine becomes a part of Russia, like the Crimea did a few years ago. Ukraine becomes smaller, more ethnically homogenous, more fiercely nationalist and simultaneously more westward looking. Russia buys a few years whilst it works out what it’s raison d’etre in world affairs is.
I hope I’m wrong and nothing happens.