Connecting input to cubase mixer

I’m using a laptop to run instruments and take the strain off the processor on my main machine. I’m using ADAT inputs for audio from the laptop but to then route that audio into a mixer channel, is the only way to hear it by activating the channel input monitor on the mixer? I can monitor via my main RME UCX but seems to be only when the input is solo’d in the RME mixer utility. If I monitor via the Cubase mixer, the latency is huge. I thought Direct Monitoring was the answer but I can’t seem to be able to hear the solo’d ADAT input as well as the Stereo out from Cubase via the UCX.

Hope that all makes sense and just wondered if I’m missing something?

Direct monitoring is one answer. You have to configure Totalmix as your monitoring mixer.