Can you please attach the system report information here?
Thank you for providing this information. I was checking the information and I just noticed the wireless driver seems to be out dated so try updating the driver. Here you can download it:
I tested this from my side with same NUC using a Keyboard branded Targus, model: AKB32US and it worked fine being next to the NUC and also I test it being 8m from it so my recommendation is to update the Wireless driver and if issue persists please contact our support center to get further assistance.