The problem is that measurements don’t tell you how something sounds. They can give you a clue but that’s it. You can have different dacs which all measure ”transparent” and still sound totally different. Holo is good example, compared to some basic Topping design or even T+A DAC200 or RME. They all measure nearly perfect but sound totally different.
So using the DAC to tune the sound of your system is certainly a thing and even recommended. Just like different amplification and speakers. DSP is yet another way to tune the sound but I only use it to fix problems with room modes. Fixing the whole frequency range has always sounded bad IMO.