The "Tyler is Voq" theory has several huge holes in it that I have yet to see anyone even attempt to fill:
1) The fact that Tyler speaks English flawlessly (there's no chance in heck that Voq could've learned perfect English in 3 weeks or less)
2) The fact that Tyler has an actual verifiable history and service record that the Klingons could not have faked
3) The fact that there's no way the Klingons could've changed Voq's internal physiology and/or made it undetectable to medical scans
4) The fact that there's no way the Klingons could've implanted the personality and memories of the real Ash Tyler into Voq without creating detectable anomalies that would show up on a medical scan
1) The fact that Tyler speaks English flawlessly (there's no chance in heck that Voq could've learned perfect English in 3 weeks or less)
2) The fact that Tyler has an actual verifiable history and service record that the Klingons could not have faked
3) The fact that there's no way the Klingons could've changed Voq's internal physiology and/or made it undetectable to medical scans
4) The fact that there's no way the Klingons could've implanted the personality and memories of the real Ash Tyler into Voq without creating detectable anomalies that would show up on a medical scan