The Zip is fine on your PC, but not on your phone, the way to prove the theory is just like I suggested...copy the ROM zip file from your phone to PC and try to extract it, alternatively you can also try to extract the zip via file manager.
This is what I was saying...the ROM zip file (which is good on your pc) got corrupted as a result of the file transfer from PC to Phone, so rather than transfer the ROM file via usb cable, try via Mi Drop, if you notice the file transfer process via usb cable, you will see it finish before 100%, resulted in a corrupted zip file.