The Russian Army is largely represented as a bunch of baffoons in the Western media, but it's still one of the 3 largest armies in the world. Ukraine cannot hold their lines indefinitely, the only way to "win" against an opponent that has multiple times your materiel available is guerilla.
There's no win for humanity through war against an opponent that has thousand of nukes. If one of the nuclear reactors in the region would had been seriously damaged you would be curse every cent that went into fueling this war. We are walking on a thin line already.