Thank you for taking the time to look at this question! Your answer made me realise that I'm not missing anything in UC therefore, so bypassed UC and created an audio channel strip in Logic Pro instead where I've added Gain as per attached image:
I suppose the question I have now is whether it is expected that you would need to increase gain on a digital piano like this, or what you're supposed to do?
I'm inputting a Roland RD-700GX on line 5/6. The piano's volume itself is modest (one tick below halfway). Would you generally boost the volume level of the piano instead?
I've found that raising the piano volume beyond a certain point increases the input too much and I end up peaking during some songs, especially when there are multiple layers of sound being generated by the piano (e.g. piano+organ). So have resorted to keeping the piano input modest, and dealing with the output to get the right volume level returned. And in this case, it seems like extra gain is needed...
I guess I'm wondering if this is normal/expected?
And from that, is there a right or wrong here for setup, or does it depend on what you're doing?