I don't see why there would be a problem. It sounds like a good idea. The D10B is a balanced DAC. The L50 and the A30pro are amplifiers with balanced input. What could go wrong?
I have a Khadas Toneboard, a D10B, an RME ADI-2, an E50 and a L50; I'm doing my bit for global economic recovery. All the devices perform well; you will not tell them apart. The D10 balanced is paired with my main amps. I love it's simplicity. Plug in the cables, turn on the amps and streamer; nothing else to do.
I prefer the RME as an HP DAC and amp over the E50/L50. It's not a performance thing. It's purely user interface, particularly on the E50. Because of the UI I tend to use the E50 in the same mode as the D10B. With the benefit of hindsight I should have purchased another D10B to go with the L50 instead of the E50.