I went back and read the OP’s original post from 10-2, as well as their one follow-up post from 10-3. I don’t believe the responses have addressed the OP’s actual questions.
It seems the OP already owns an EVERSOLO DMP-A8 combination network streamer/DAC/preamplifier that you can read about here, and also a McIntosh C53 preamp, which also includes an onboard DA2 DAC. The OP is apparently using the DMP-A8 as a streamer only (presumably connected to their network via Ethernet LAN), and then to output a digital signal via coax to the C53, which is performing DAC and preamp duties.
The OP’s questions, as I understand them are:
Original question from 10-2: Should I purchase a MacBook to replace the DMP-A8 streamer. Answer: Probably not. Based on what I have read of the DMP-A8, it should be competent as a streamer and, since it can output a digital signal, you can use it as a streamer only, and bypass the DAC and preamp sections of the DMP-A8 in favor of the presumably superior (in your words) DAC and preamp sections of your McIntosh C53 DA2.
Second question from 10-3 post: Should I change the digital coax cable I am using to feed the C53 to a giga lan or usb cable? Answer: The C53 does not appear to have a LAN input, so no to that option. Regarding coax vs. USB, my experience is that with all but the most optimized DACs, I like the sound of the coax input better than USB. However, every situation is unique and it would be very easy for you to A/B compare your coax cable input into the C53 against using a USB input, since the C53 takes either. Therefore, try both and choose whichever connection sounds best to you.