>they'd be gambling that NATO doesn't launch things into Russia

The official discourse in Russia is that NATO is already helping Ukraine launch things into Russia. So there's no gamble; for them, it's already a fact. Except, currently, it's just a proxy war where Ukraine has to jump through hoops to get military aid and targets approved, and it can only fire from Ukraine's territory. With a direct confrontation, there's no doubt that far more would be launched into Russia.