Long digital or balanced cable run?

Sorry! Reading your post it sounded to me as if you were considering implementing a longer coaxial cable from your streamer to dac OR balanced from dac to pre. Even if you’re using AES for digital the document sent will provide you with the distance limits for AES. 
Either way you’ll have more success using balanced if distance is the primary consideration.

Not sure either will produce better sound but one might degrade some but I doubt the length of cable you are referring to will make a difference. Why you would want to put more distance from source to DAC may not be ideal, So I would go for longer balance to amp if needed. 3M of other isn’t going to make much of a difference so if it’s cost/budget then maybe go that direction. If I’m going to chance picking up noise with longer cable runs then stay with balance as it cancels out the noise meaning a lower noise floor. Your AES EBU is balance so if your amp is not truly a balance circuit then the longer digital cable.

Balanced audio is better for longer cable runs and when those cables are around a high amount of electric signal. Unbalanced audio works best under 10 feet and in a smaller studio environment. Balanced cables are more resistant to external noise or interference due to their capacity for common-mode rejection, as answered in the previous question. Common-mode rejection allows for balanced cables to have less noise in the signal path. Prepaid Gift Balance
 

I think for the lengths you're talking about it make zero difference. but what type of digital cable is the question? optical would make zero difference at these lengths, wire run would have more effect and you'd be limited by the type of cable and standard you're transmitting. Cat 5-6, RCA, AES SPDIF, USB etc. All have different parameters. Most digital transmation systems have robust error correction as well. but a true balanced system also has inherent noise rejection. so, you may have to try it but i suspect you're not going to hear much difference at 3 meters. 

If you use the right balanced cables you can probably use it to smooth out some top end harshness, but that is all.   Personally I'd go with inexpensive digital and nice, short XLRs