How important is gain flatness to a receiver?

I’m designing a system to add path propagation effects to RF signals, making the ground test signal have the characteristics of a much different intersatellite link. For modularity and monitoring reasons, the system has a lot of components (cables, switches, couplers, amplifiers, attenuators, etc.) with non-uniform gain across the operational frequency range.

How important is that gain flatness to the signal? With my current components I’m looking at net gain gradients between 5-20 dB/GHz through my design in the operational range. I’m hoping this is okay for a 200 kHz bandwidth signal that I start out with, but the system may need to support a 3 GHz bandwidth spread-spectrum signal. Will that be a disaster in terms of signal performance when I pass the signal to a receiving radio?

Edit: The frequency range is typically 1-2 GHz, but the wideband application will extend up to 4 GHz. That’s based on limitations of some of the equipment imposed on the project, so both ends will have frequency converters as needed (E.g the 3 GHz band signal will be downconverted from Ka-band to apply the link effects, then converted back up to the original frequency)

Edit2: I found the issue was an L-band amplifier that snuck into the analysis. Removing that, it’s now a pretty smooth 3dB/GHz slope from 0-6 GHz. That can be fixed with an equalizer so I think we’re good to go. Thanks!