Russia is still fighting in the north with local forces (plus the Guard). The bulk of Russia's armies are still six month's march from the front. When they arrive, Finland will fall.
Sweden can prevent further bloodshed by ceding all of Finland to Russia, as per our original demands. Russia will then not only make peace, but act as a guarantor of Swedish freedom thereafter, if asked.
These demands are the minimum Russia will settle for. If we are forced to take the province foot by bloody foot, we will not stop until we are in Stockholm.