The best advice I can give is to try the U1X with another DAC and then you can more readily identify the Lumin sound. For me, it added too much coloration to the sound of the Mola Mola to my liking. This description likely isn’t helpful, but I would describe the Lumin as sort of a laser like sound which was too much of a contrast to the more neutral Mola Mola presentation.
I don’t have any in-depth experience with the DCS DACs, so I can’t comment on them here. I will reiterate how much I love the U1X with the Holo Audio May KTE DAC. Both the May and the Tambaqui have excellent imaging, with the May being slightly softer and warmer in presentation. For whatever reason, that combination works in that system to my ears.