Shielding effectiveness system
RG213 is a badly shielded low cost cable for a few hundred MHz at most.

For your application you'll need 086 size rigid coax, just over 1 mm thick.
Rigid or semi-rigid coax has a solid braid, so up to 100 dB screening. (but probably not at 9 kHz). At 40 GHz you'll need very thin coax, which is unfortunately very lossy.

Brace yourself for the price of 40 GHz connectors, hundreds of dollars each. You can't use N-type above 10 GHz or so.

You might consider separating your whole system into different frequency bands. The antennas and amplifiers will already be quite band-specific. Then you could use 141 or 250 size rigid coax for the lower frequencies.