Windows might decide that for you. If win 10 recognizes the PC supports GPT it will insist on using it during the installation process. It does depend on how bios is set up. If you have it set for legacy boot it will use MBR. But if the bios is set to auto or some variant of auto, it might swap to UEFI boot on restart.
Most modern Motherboards set up for UEFI boot method by default now.
Above is correct, it only really makes a difference after 2,2tb. And really only for the boot drive as I believe storage drives can be formatted as GPT on MBR systems already?
GPT max size is 18.8 million tb, we shouldn't need to swap again in a hurry