None of the proteins of this Virus had been known before. Even if hypothetically the Virus would have been constructed out of Bat viruses only known to some top

None of the proteins of this Virus had been known before. Even if hypothetically the Virus would have been constructed out of Bat viruses only known to some top-secret Chinese scientists, there is no way they could have known those components to be "deadly" (to Humans). You underestimate evolution and wildly overestimate the capabilities of genome engineering.