Does Ukraine Have To Win The War, To Get The Russians Off Their Soil?

 No.  

Every single day, there is a fraction of the Russian economy that is subtracted in some way.  Germans don't buy natural gas.  Russians can't travel internationally like they did before.  Various companies don't market their wares in Russia. The list goes on and on.  

In the first hundred days of the war, this fraction didn't really add up to be anything that the typical upper-class Russian would notice.  

When things reached the fall period, with the reservists activated, and near three-quarters of a million Russians exited the country (saying they won't return)....the fractions started to add up.

By this point, the losses of aircraft, tanks, and weapons add up.  You spent x-amount to reach this stage of the war.  You should have 'gains' or something to show for your efforts.  Russia has nothing to show. 

The dead Russians?  Generally, even if you use the fairly conservative numbers (discounting anything that the Kremlin says)....you can probably say around 100,000 Russians are either dead, or wounded enough to never be an asset for the Army. 

People who watch the nightly propaganda show on Russian state TV....in the past month....have noticed various moments where the economy in Russia has been brought up.  It's not very positive, and the GDP business is coming into focus now. 

I would suggest that Ukraine only has to drag this out, and the Russian economy will be the 'iceberg' to sink the ship.  

China looking at a ailing Russian economy?  China values trading partners and people that they can sell stuff to.  If Russians have marginal money....they don't buy Chinese stuff.  It's hard to see how this trade business continues on....like it was prior to the war.

The problem that Russian developed into over the past thirty years?  They bought into western technology....even to the level that you need certain technology to operate the natural gas and oil pipelines.

So just dragging this on...creates a weaker economy and a more dependent Russia in the end.  Ukraine doesn't have to win....just make the Russians economically weak.