In terms of the costs for the naked aggressor:
- Economic destruction
- Loss of any remaining European understanding (outside lunatic fringe/payroll)
- Diplomatic isolation
- Loss of influence in Central Asia
- Military crippled and fearsome reputation gone
- Educated youth fled abroad
- Ukraine now with strong national identity and strongly anti-Russian
As for the “gains” column, they have a strip of devastated land which they can, at best, try to hold in a frozen conflict at the cost of further destroying their country’s future.
I honestly struggle to think of a parallel for such wanton self-destruction (Don’t mention the “B” word - that almost seems sane by comparison).