Yeah but I mean just from the point of view of having a decent PCIe to i2s board for ease of connection direct from PC to R26.
For A. creating an i2s connection in the 1st place and for the primary reason, and B. ensuring a clean signal from PC to DAC
If the clock of pink faun is not on same level as Gustard, the I2S board makes no sense, despite the ease of connection.
I have looked up pink faun super oxco clock for you. For €1250 you get -100db @ 1KHz phase noise, which is not that great.
I cant find info about the Gustard K2 clock but my instinct tells me it is in the same bull park as pink faun.
So, if you want to get the most of the Gustard r26, then you go with the LHY SW-10 ethernet switch which has a (presumably, rumor says) better clock then Gustard K2.
With this combo, you use the Gustard in etherned mode clocked by the Switch.
You get clean ethernet and since the R26 has a 10 MHz clock input and the SW-10 a clock output, you can synchronize both devices, DAC and Switch on the same clock, which is preferable from a technical stand point.
If you dont want to spend €1500 on a audiophile switch and coax cable, then you go with the media converted or WiFi extender mod on page 1, which costs you around €200 depending on the linear power supply you use and gives you the best bang for the buck.