P.S.
I have some programming experience (mostly Python), however all in Radium is very new for me now, so it's hard to predict when I will be able to add anything useful.
But if developers need it - I can help with testing!
Yes, Radium supports MIDI learn. First enable MIDI input for the device (port) you want to use under MIDI -> Midi Preferences, then right click the slider or checkbox you want to MIDI learn on and select "MIDI learn".
Afterwards, you can remove and enable/disable MIDI learned parameters under MIDI -> MIDI Learn Configuration.