UPDATE: As suggested by AnalogSummer, I came back to ReaLearn, but by default some buttons have same values, because for some reason almost everything is on channel 16...?
I fixed it by creating a custom mode in Novation Components, assigning buttons to different channels, and I can finally set everything properly!
OS: Windows 10
MIDI Keyboard: Novation Launchkey MK4
My drivers are updated to the latest version.
According to YouTube tutorials, I'm supposed to go to Preferences > MIDI Inputs & MIDI Outputs, enable my device, then go to Actions > Show action list... and set everything up. My problem is that not every button is seen by Reaper. For example: I can't assign my record button, it doesn't detect my input at all (I enabled "Input, All, Control" in MIDI Inputs and "Enable, Clock" in MIDI Outputs).
Official Novation support on the other hand recommends setting it up via adding HUI (partial) Control surface mode in Preferences > Control/OSC/web. It works to some extend as most of buttons are assigned automatically (I can control volume, panning, and recording works, too), but with this, I can't edit anything manually in Actions, so there are still buttons that don't work or I can't adjust to my liking.
I also tried using ReaLearn, but some of the buttons are detected in the same way, so behavior of it is quite unexpected (example: My undo button has the same Type, Channel and CC as my 7th volume slider, so when I use the slider it undoes everything instead).
Is there anything I can do about it? Has anyone had problems with this? :')