Running a truly balanced output is only beneficial if the receiving component has a truly balanced input circuit.
@soix ^^ This.
Don't bother with the XLR output since your preamp can't take advantage of it. The RCA connection will work just fine. The adapter will simple convert the balanced output to single ended and if pin 1 is shorted to pin3, you could possibly damage the DAC (so usually this connection isn't made with many adapters). If it works that way you're only listening to single-ended anyway. So just use the RCA connection.