Ahh sorry didn't noticed. Its not for cactus it's for sakura (redmi 6 pro) BTW. And looking at this site I don't think there will be miui 12 for your device.
Make an effort searching before posting.
We don't support any Mediatek devices (like Redmi 6 and Redmi 6A).
Redmi 6 Pro has Snapdragon so we supported it.