It depends on how the DAC in the H95 is implemented. If the DSP it applies is specifically only for ANC and transparency and goes more or less passive if both are off (besides transcoding for BT), then you actually might see a gain using an external DAC. However, if the DSP does more than just that, then it’s likely all the gains you’d get from using an external DAC would likely be lost. The main gain you’d get out of using any DAC though, still stands, you get a higher bit rate. Granted it doesn’t apply to lossless, any sort of transcoding done on device vs the headphone (assuming the device is superior to the headphone) would also be an improvement too.