Focusrite 6i6 comes with the same coaxial RCA S/PDIF connector as the KPA has. With one small S/PDIF cable, you can carry a stereo signal, or two separate channels to your DAW.
S/PDIF does not perform another Analog to Digital conversion, your untouched Kemper sound is sent directly to DAW/disc.
You could plug your monitor speakers directly into the Kemper, or the Focusrite 6i6 at that point.
96Khz at 128 Samples gives me a round-trip latency value of 7.21ms, with a Focusrite 18i8 and those settings. No lag feel here.