I am not sure about 1945 Finland. but current Finland is of no interest to Russia. there is no logic to compare Finland with Ukraine.
Russia gravitates towards South. You can see the wealthy Russians connection to Israel. Russians buying real estate in Turkey.
Enormous cost to develop Sochi and Anapa. than you can add Crimea and its infrastructure. Southern and Eastern Ukraine comes in same category but added benefit of resources. Ukraine hasnt offered much resistance except for holed up in the cities.
credit is given to people of south with clear identity.
You completely miss the point. The comparison is not between Finland and Ukraine as countries today.
The comparison is between a victorious USSR in the Continuation War (to use the Finnish name) against Finland
and a supposedly (or hypothetically) victorious Russia in the current war against Ukraine.
My point is that even Stalin did not press for the maximum war aim of conquering Finland and adding it to the USSR.
Even if Russia prevails in the current war, Putin may be prudent enough not to aim to conquer all Ukraine.