Are you aware of the fact that the analogue input of the WiiM Amp Ultra is digitised straight away?
So the signal from the CD BOX E (digital) goes to the Dacmagic coaxial in,
from the Dacmagic 200M (analogue) XLR to the WiiM Amp Ultra's RCA line input,
from the Amp Ultra's (analogue) line input to the Amp Ultra's ADC,
from the Amp Ultra's (digital) ADC through it's digital processing engine to its DAC,
from the Amp Ultra's (digital) DAC to its power stage input,
and finall from the Amp Ultra's (analogue) power stage input to its analogue power stage input.
I'm aware of the fact that the CD BOX E has no optical output and the WiiM Amp Ultra has no coaxial input, but whatever you do, the digital CD signal goes thoug the first DAC (Dacmagic), then through an ADC and finally through the second DAC (inside the Amp Ultra).
Unless the Dacmagic adds a lot of (non-neutral) "sound signature" to the signal or serves additional purposes, a digital to digital converter (coax to optical) was a more cost-effective solution.