Other than mmwave (which this modem does not support), I don't think there's much more magic to do in an empty vs. a congested cell for a baseband. 5G spectrum

Other than mmwave (which this modem does not support), I don't think there's much more magic to do in an empty vs. a congested cell for a baseband. 5G spectrum is managed by the network, so the only thing that will happen is that each device will get shorter/narrower time/frequency slices, but there shouldn't be any unexpected cross- or same-channel interference of the type that is common for unmanaged protocols like 802.11 or Bluetooth.