A client just purchased a new iMac a few weeks ago. After completing the setup and migration all of their files, we noticed a "low memory" warning appear every time the iMac was rebooted

At first, I thought this was adware/PUP, but eventually believed this to be a legit Mac OS popup. I used Activity Monitor to monitor resources, but the only processes consuming memory (not CPU), was WindowsServer. I checked but did not see any out-of-place apps that could be causing issues.
I ran a malwarebytes scan on the system, but it came back clean
I also checked the Startup folder for the primary account, but it was empty
After closing/acknowledging the warning message, it does not appear again until after the next reboot. While this is a cosmetic warning message, there does not appear to be any sort of performance impact on the system. Nevertheless, it would be nice to kill this popup.
Tip: My iMac is fairly quiet, only running processes - Mail Client, Browser, Skype, many ssh sessions - which normally eat up 17G+.
So if I had <32G memory, this machine would be swapping.
If I run ffmpeg doing an HEVC transcode, using massively long lookahead buffers, all 32G of memory gets eaten up instantly.
Guideline: These days, 32G memory as a minimum to ensure no swapping, as once swapping starts, machine death can be quick.
A low memory message normally appears, just prior to machine death.
Run Activity Monitor looking at your memory usage.
16G - machine will be slow + likely survive.
8G - machine will run low on memory all the time + life will be a constant struggle.
If this is a new Mac with <32G, person might be able to return it for a 32G machine.