My question is simply how long could the 62 Finnish Hornets stand up to Russian air power ? In short, is the expendure worth it, or could the Euros be better spent on other anti-Russian weapons ?
I supported Hornets for two deployments to Southern Watch in the 1990's when I was in the Navy. Overall, the hornet is a very capable multimission aircraft.

On your first question, without additional context, the answer has to be "it depends." If Finnish training and tactics are comparable with the US, I think they could do quite well against the Russians, assuming they have a robust air surveillance and C3 network to support the aircraft.

On your second question, any answer is going to be subjective. It seems Finland's primary goal is deterrence and for that purpose I think a multirole aircraft like the hornet is a decent choice. If deterrence fails, and when the aircraft are fully air-to-ground capable, the Finnish hornets will provide a flexible force able to respond to a variety of threat scenarios.