I believe the only advantage with optical over coaxial SPDIF is you can avoid ground loops, RF and electromagnetic interference.
Also “High Res” audio is anything over 16-bit/44.1kHz. So 24-bit/48kHz, 24-bit/88.2kHz, 24-bit/96kHz, 24-bit/192kHz, etc are all “high-res”
Whether or not you can...