Interesting... I thought coil whine only occurred with desktop gpu's, but a quick search for - ASUS ROG G16 gpu coil whine -
revealed it can happen with laptops as well. I found a number of links for your laptop model regarding this issue,
so odds are this is what you are hearing.
I believe coil whine does not always have the same pattern relating to fps, or how much or how little the load is on the gpu.
Apparently some people are more susceptible to the frequencies than others too.
My understanding is there is nothing that can be done, by the user at least, to fix graphics cards with coil whine.
If it's unbearable and the machine is still new enough you may be able to return it and get another, that with a bit of luck does
not have this issue. Being able to swap for another may also depend on where you bought it and if the coil whine is happening
when the tech examines the machine, and if the tech is equally susceptible to the frequency.
.