“ JW dogma places Jesus’ presence before the great tribulation, but Matthew 24:21, 29 clearly places it after the great tribulation. ”
That is not how Matthew 24 works. Matthew 24 starts off with Jesus telling his disciples about the destruction of the temple.
Jesus is then asked three question. When will this be (destruction of the temple), what will be the sign of your coming and the end of this age.
Jesus then answers. Their generation will not pass away before the temple is destroyed.
Jesus borrows apocalyptic judgement imagery from Daniel 7 of the son of man coming on the clouds. The same imagery he tells Caiaphas he will see in Matthew 26.
Only starting in Matthew 24:36 does Jesus then answer about the end of the age. It will be unexpected.
The great tribulation Jesus speaks of is the events leading up to the destruction of the temple.