That's a very weird way of phrasing that Russia has barely anything to gain while Ukraine has everything to loose. It's not like Russia needs any further territory, they are the largest country and haven't yet properly integrated the already invaded cultures.
But did those countries still have multiple generations that remembered what the invaders did last time they controlled them? And was what the invaders did as bad as the actions of the USSR?
I don't think USSR did anything specifically bad to Ukraine after ww2, in contrast, Ukraine gained lots of territories, soviets invested heavily in Ukraine, as result Ukraine became leading industrial and technology region of USSR, most developed and educated compared to all others parts of USSR with exception of handful key regions in Russia.
In fact it is common knowledge that before 2014 Ukraine and Russia were brotherhood nations. Ukraine couldn't imagine being attacked by Russia, that's why the army was a joke at that time and Putin took over Crimea so easily.
