There are reasons why the EU should support the Ukraine, but access to the Ukrainian market isn't one of them.

The Ukrainian GDP is 179 billion USD (https://tradingeconomics.com/country-list/gdp?continent=euro...); they're a market smaller than Greece (244 billion USD) or Hungary (212 billion USD). If they succeed in driving the Russians out, they'll have to rebuild their country and will probably be in debt for decades.

Democracy in Russia is a pipe dream; they have nuclear weapons and Putin isn't about to give up power. I guess it's possible that his successor could hold elections, but that's highly unlikely at best.