3 possible outcomes I reckon:
- Pressure on Putin will make him retreat or broker some sort of temporary peace deal (perhaps annexing the two smaller eastern Ukrainian areas already "declared independent" and sticking with that - again I reckon this is only temporary and possibly only prolongs another mammoth attack on Ukraine in some years into the future). This may reduce some sanctions again.
- Putin continues the onslaught until Ukraine waves the white flag. No sanctions dropped and could cause more trouble.
- Putin continues the onslaught until Ukraine is completely destroyed. No sanctions dropped and could cause more trouble.

Forget about it. There's no Ukraine anymore. There's only Ukraine Oblast of Russia. Putin is not going to stop.