Depends heavily on what class of DAC/AMP we're talking about. If the combo is about the price that EVGA costs there will be no difference or EVGA will even sound better.
But, just for example here, i've switched to external Sony DAC/AMP for 2k$ and yeah, it sounds better than EVGA :D
But it's not suitable for games, the sound renders with a delay.
So in short... Yes, GOOD external DAC/AMP will beat ANY soundcard ANY day, CHEAP DAC/AMP will probably sound just the same. 

BT ? You mean DT 990 Pro ?

ok tanks guys :) 
yeah I hesitated between the audio card or the schiit
 

I asked the same question in an audiophile discord server because I bought the Nu Pro and was contemplating returning it for the Schiit AMP/DAC stack. Initially the people in discord were ****ting on the EVGA NU Pro and said any DAC/AMP combo is better than a PC sound card, but then one of the knowledgeable and respected members of the community who works as an electrical engineer with a senior position at an audio company said the Nu Pro takes a dump on the Schiit stack, and it was the better choice. 
 

Tanks for the answere