Well, the the dCS bridge is not native I2S, then then I2S is not a standardized interface. Synergy is only guaranteed if source I2S is made / designed by the same company than receiver I2S. Some companies offer I2S and in most cases it are proprietary interfaces, different connectors, even if the I2S connector is HDMI, the pins may be different, signal clock rates, energy levels in peer supply lines etc. etc.
AES/EBU is a standardized interface just 3 rugged very good contact pins, fully screened, like I said, designed for high end audio and studio applications.
I see the benefits of PS Audio’s I2S and I would certainly utilize it if my source had a 100% compatible native I2S output like the Direct Stream Media Player.
But do you honestly think the extra cables, connectors, electronic company’s/chips in the signal path are going to enhance the native AES/EBU signal. If it would require that, why would PS Audio have added the high quality (expensive) AES/EBU interface?
For USB I can imagine that cable and improvement box affiniados utilize a box and extra cable in between. I just cannot see the benefit. Put your money in a dedicated good AES/EBU cable. Be aware, although the connectors are identical, the impede fence of AES/EBU cables differ from the analog XLR cables, since you are quality minded about the connection, my recommendation would be to buy a dedicated good quality AES/EBU cable.