First, just to be sure, we are talking about the Broadlink RM pro device, correct?
"IR"means infrared, and it always works the same way, although different devices transmit different codes using it.
“RF” means Radio Frequency, and covers many different frequencies as well as different codes. Wi-Fi is RF, zigbee is RF, Zwave is RF, Ademco (345 MHz) is RF, Lutron clear connect is RF, 433 MHz is RF-- and a device receiving on one of these frequencies cannot even hear any of the others, let alone understand the codes that it is sending.
2.4 GHz is an RF band which is popular for a number of different protocols, including Wi-Fi, Bluetooth, and zigbee.
The RM Pro can do WiFi and two other RF frequencies:
The RM-Pro will control all RF devices/appliances working on the 433MHz & 315 Mhz frequencies .
No zigbee, no zwave, no Lutron.
433 MHz and 315 MHz are both popular for devices with short range simple button remotes, particularly audiovisual equipment and some HVAC equipment like fans, so that’s probably why Broadlink RM Pro selected those. But even though its marketing description says “universal RF,” it’s definitely not. It’s limited to devices on those two frequencies.
So I’m not quite following what you’re looking for. 2.4 GHz is an RF band.
If you mean specifically something that will work with the Broadlink RM pro “RF” option, then you’re looking for devices with remotes that operate at 433Mhz or 315 MHz (neither of which, by the way, is supported by SmartThings).
If all of that’s correct, just let us know, and then people can suggest appropriate devices for what you’re looking for.