For 20 dB of voltage gain there's no need for very large resistance values. Using very large values is done sometimes in transimpedance amplifiers, but then may require guard rings and PCB cutouts to manage unwanted trace currents. In extreme cases, IC dice and wire bonding may be required to avoid leakage between pins in epoxy packaging, though that is rare and more for delicate experimental systems. In your case, there's nothing achieved by large values to even consider the idea.
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