I don't know much about the Mytek line, but they have an interesting approach. The Mytek offers the choice of analog & digital volume control. Indeed, there seem to be a lot of similarities between the Brooklyn & P6. Both have preamp facilities (additional inputs, including phono sections, volume control) as well as DACs (both appear to be based on the ESS 9018, even). Have you compared them against each other, section by section?
The P6 is much more flexible, with more inputs, home theater bypass, bass management, etc. If these have value to you and the DAC sections sound acceptably close, consider selling the Mytek & using the P6 DAC while you ponder your next acquisition. If the Mytek works for you as a standalone preamp, you could do the reverse.
If all of your sources are digital, source switching really occurs at the DAC. In that case, a DAC with a satisfactory volume control could be all the preamp you need