But other than that the European militaries haven't done any real fighting for many decades.
The US fighter planes and armour haven't faced a real opponent in a long time either. Most of the experience is in asymmetric warfare against guerillas, which would be very different from a war against Russia.
I have doubts about actual battlefield performance of the main part of the army, in part because because there is no data.
No data does justify uncertainty, but you can't just say "I don't know how well the German army would perform, therefore I'm going to assume they'll do badly". Anyway, there is data from wargames, from testing grounds, on what distance a weapon can hit a target, and so forth.
It's been more than twenty years, but the first Gulf War was a conventional war waged against an opponent that was serious about fighting conventionally. The strategic outcome wasn't really in doubt, and the Iraqis at the time were largely running old and/or downgraded export versions of Russian equipment, but it still gives us good tactical data; the current reputation of American armor, for example, largely rides on the Battle of 73 Easting.
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