Please don't be critical about the identity of Jesus and Jehovah.
JWs got it right.
But with Regard to Rev 22:12, it does not give an identity. However since vs 13 says " I am the Al′pha and the O?me′ga", it is Jehovah speaking
and " the first and the last, the beginning and the end." would also apply to him too without affecting Jesus.
Since there is no change between vs 12 and vs 13, vs 12 would also be Jehovah. But the verbage could also refer to Jesus.
However, since vs 16 says ‘I, Jesus, sent my angel", which would indicate a change in speaker, then vs 12-15 would be Jehovah.
Why does it matter what the Watchtowers, Awakes and books say? The Bible is not clear on the issue.