I'm curious as well. While WiFi, BLE, and BLE 5 are sexy, a lot of real industrial work is done on sub ! GHz.
SUB 1 GHZ radios are going to require more flexibility in the parts, Oscillators, filters, antennas... what freq band are you wanting to use? The sub 1ghz radio could be better as an external device, no reason why you could not interface a PSOC6 BLE device to a much bigger and powerful radio. Ham radio 440mhz <> BLE <> Laptop or Tablet device. How far do you want to transmit?