If memory serves me right then we had this topic already in the forum, there is no difference.
Digital transmission is lossless and you can proof this yourself with an ADI-2 Pro/DAC by performing the Bittest.
Better than lossless / "bit perfect" transmission is not possible.
With the ADI-2 DAC/Pro the final D/A conversion will always happen with the internal FS clock.
The Steadyclock based design decouples external and internal clocks with the goal to eliminate any clock jitter from outside and to deliver an optimum D/A conversion with the internal femto second clock.
Detailed information about RME SteadyClock technology you can find here:
Otherwise .. the use of ADAT / optical SPDIF (via TOSLINK cabling) is recommended because of the galvanic isolation between devices to fully avoid any potention problem with hum.
X10SRi-F, E5-1650v4, Win10Pro21H2, Cub10Pro, UFX+, XTC, 12Mic, ADI-2 Pro FS R BE, RayDAT