Welcome to the WHF forum.
I’m a bit confused by your description. We usually describe the signal from source to speakers. So I think you’re saying:-
iPhone 14 source > NAD C368 amplifier > KEF R3 speakers. Is that correct?
Are you trying to avoid Bluetooth for your streaming from the iPhone? If so, why? If you want an alternative, I believe the NAD has a streaming capability. Please explain what you are trying to achieve and we might be able to help.
NAD spec for reference:
https://nadelectronics.com/product/c-368-hybrid-digital-dac-amplifier/