Here the OP says that his/her "xth(x>=10) replacement is quite acceptable":
https://forums.macrumors.com/threads/2018-mbp-15-coil-whine.2128494/page-9#post-26806590
Two separate products. Similar issue, sure, but I personally wouldn’t deal with the hassle of swapping it out, possibly multiple times, in the hopes of landing one with a less “perceptible” noise. To each their own though. Not dealing with a quick firmware/software fix here. I do notice it but it’s not a deal breaker for me in the slightest. I was/am more simply curious of the cause from an education standpoint. I’ll just move mine another foot away from me if it ends up overly annoying me, which I doubt it will. I understand this won’t do for others.