This is also very conveniently a Russian talking point to just make Ukraine bend over and take it.
If we want to stop the risk of nuclear war from increasing drastically in future we need to help defend Ukraine itself from Russia to the fullest.
If we don't, it will become clear to the world that only nuclear weapons can defend a country from having their land grabbed by Russia and other countries and nuclear proliferation will go through the roof.
Nuclear proliferation going through the roof will drastically increase the chance of a nuclear exchange in the future.