Es klingt nicht besser oder komischer als das Original

I disagree. "Kühn" and "klug" are not contradictory, but "bold" and "prudent", while not exact opposites, are quite far apart in meaning.

I'm still thinking about it, but perhaps something like "she collected contemporary painters in a cool and calculating manner"?

how about ingenious cleverness?

raffinierte Klugheit

That's just redundant though, isn't it?
And to me it's missing the element of calculation in "kühn".