Greetings, I have bought RX 6600 10 days ago and I was using it normally till today.
Today, I opened the "Instant Replay" and "Record Desktop" options from AMD Adrenaline Software and I realized I was having coil whine issues, when I turned it off, it returned normal as if nothing happened.
I wondered if it was related to my software or hardware, so I reached out my friend who use RX 6750 XT, when he also opened those settings, he started hearing Coil Whine as well.
Both mine and my friend's Adrenalin Version is 23.9.1, we are having same issues so it may be driver related, fyi, good days.
First verify if the Coil Whine is coming from the GPU card and not from the PSU or VRM of the Mobo.
Coil Whine occurs in high powered electronics like the PSU, GPU, or VRM of the Mobo. It is possible the GPU card is getting more power than normal when you are using those options in Radeon Settings.
Try downgrading the AMD driver to a previous driver and see if the same thing occurs. If it doesn't than I advice to open a AMD SUPPORT Ticket and let them know from here: https://www.amd.com/en/forms/contact-us/support.html