The plot is incredible messy and it's filled with massive plot holes, retcons, and continuity errors.
Megatron was Galvatron from Age of Extinction, so is he Megatron again?
Optimus claimed that he hasn't heard Bumblebee speak since the fall of Cybertron, even though he talked (though temporary) in the first movie.
In the first movie, Optimus Prime says they learned Earth Language through the World Wide Web, yet the transformers can talk English normally during the King Author era.
Speaking of which, after the first movie, Bumblebee doesn't talk in the other Transformers films, but in here, he does without any explanation why.
Cybertron was said to be destroyed in the previous movies, yet in this movie, it's actually still…