Two setups of Windows 10 were implemented.
Two setups of Windows 10 were implemented.
You'd need to ensure proper isolation between drives during installation. Simply moving the old drive to a new one isn't sufficient—you may want to follow specific steps to prevent data loss or corruption.
Windows sometimes takes on characteristics of another version. Using a hybrid UEFI+CSM installation with both legacy and UEFI setups could be possible.
Windows can sometimes play tricks with bootloaders. To avoid issues, remove the old disk, plug in the new one, and install Windows so it doesn't conflict with the existing boot loader. The new drive will have its own bootloader. After that, reconnect the old drive and choose the appropriate Windows Boot Manager or drive from the BIOS menu. You might need to adjust BIOS settings between legacy and UEFI if you want both on the same machine. It's usually simpler to install both versions at once for now.
If they're both legacy, it should definitely work. I'm being honest—I didn't really like UEFI before, but legacy seems better to me. Hopefully it will function as expected.