So what is your strategy for keeping the dudes flowing along side of the guns and money?

You're extrapolating to infinity. Yes, Ukraine will run out of "dudes" before Russia does, all else being equal. Despite the unequal casualty rates (which strongly favors Ukraine). But you don't have to go to infinity. Or even five years. Within two, assuming Ukraine continues to get materiel from the West, Russia will be exhausted. Their economy will be a shambles (it's not great now). Their military capabilities will be further degraded. They will need this conflict to be over.

You don't need "dudes". You just need to encourage your enemy to give up and go home. Several examples of that, including 'Nam, Afghanistan (twice!), and pretty much all of the old colonial powers that no longer have colonies. They all resisted until the occupying/invading power just gave up and left.