Yes, it’s possible to have combinations in DT_InputActionList.
Press the little plus symbol on primary or secondary combination to add keys to that combination.
https://i.imgur.com/QWOcvwA.png
If you change default values in DT_InputActionList, you might want to reset the settings save file so you can load default bindings and see that they work.
https://i.imgur.com/RatoUPO.png
Sorry for the late answer, this should work with most projects. The keybinding system only gives you the events from rebinded keys, similar to the standard events in engine. It’s up to you and your game to receive those events and react to it.