AVE10N Historically, yes, removing the CMOS battery would clear BIOS settings. I am more familiar with Apple computers, so the equivalent was when settings were stored in "parameter RAM" (PRAM), which would be lost when power is removed. However, on Apple computers, this was transitioned into NVRAM (non-volatile RAM), which is a section of the firmware/BIOS EEPROM chip which stores UEFI variables/settings (these persist through power loss). How this works on Windows PCs these days is not fully understood by me, but it would not surprise me if UEFI variables are not reset when removing the CMOS battery.
Probably the easiest way to investigate this is in Linux, exploring the "efivars" filesystem. You could also (if possible) dump your entire firmware/BIOS chip with a programmer and use something like UEFITool to analyze it and possibly delete existing variables, then flash it back. However, these are advanced techniques. Also, the relevance of any of this to your eye strain issue may be limited. I only brought it up because you say something changed and it persists across an operating system reinstallation and affects multiple GPUs, which leaves limited options (if not a neurological issue).