You picked the one with the worst effect for Russia out of three, yes, but still won by Russia, so what was your point exactly?

And have you ever seen any footage of actual fighting in Ukraine? It's either armored units getting butchered in the open fields, or tree-lines being the only safe means of approach and defensible entrenched positions.

Finland is exactly the type of terrain that enables modern military action. Unless you're expecting NATO to use heavy cavalry, or (the earlier) battle of Kursk style mass tank formations, which is by now even less likely then cavalry. Pick your favorite highway of death between the Iraqi and the north of Kyiv one for a reality check my dear tank aficionado. Not to mention the absolutely spectacular position of Severomorsk - northern fleet command, relative to NATO borders nowadays. Or the fact that Russia is in reality so scared of NATO that there's hardly any equipment or experienced troops left in that region currently as a cherry on top.