I think Russia since they can support it in the long run, but it 100% means nothing at this point

Depends

Russia has more troops and money

Ukraine has the advantage of their gun designers being actually f**king competent

There will be no winners.
Ukraine is trying to hold out long enough to get Poland (and theoretically NATO) involved but their country has no chance of surviving the upcoming WW3.
Russia's plan to corner the market on Europe natural gas is going well so far, as they have taken over most of Ukraine's port cities. But they have no way to hold onto anything they take outside of the eastern Russia speaking cities.
So you just have Afganistan with nukes.