Feel free to use secure boot and pure UEFI mode if you want, but I’ve tested it on every system I’ve had (current is z590 and 10850k) and prefer MBR. For the casuals and weirdos that claim no settings in the BIOS or Windows have any effect on gaming, all it would do is stop you from running a 4 TB boot drive, so who cares.
Are you confused, maybe? The alternative to UEFI isn’t MBR, it’s CSM. And yes, the partition table switch to GPT is a part of UEFI boot, but that’s a separate thing to talk about. The idea that MBR vs GPT would have any effect on “gaming” is nonsensical.
Oh, and running in CSM also makes you unable to use ReBAR which, I suspect, would have a far larger effect on gaming than whatever you are trying to achieve.
And yes, “casuals and weirdos” will continue claiming that, VBS on older CPUs aside, pretty much no Windows and BIOS snake oil tweaks over the years have achieved any actual benefit. And until you can, unequivocally, using actual measurements taken with LDAT, prove otherwise you will be ignored by the sane enthusiasts. Your tales of “clown cursor” and “mouse feel” are not proof, you understand.