In the planned Ascension of Earth, is the missing piece whether humanity goes with Earth or stays behind to experience either greater levels of slavery or annihilation?

The Ascension will happen with both or with none. So the eventuality will be determined by what humans do to deal with their interlopers who are obstructing things and limiting future prospects with their presence and the level of control they maintain. If this is overcome by enlisting divine help, both Earth and human will ascend to higher dimension and leave the 3-D behind to others. That is the intention and as it should be. There will be other beings still within 3-D who will be needing to solve their own dilemmas, but the human will be moving on to other opportunities and duties and need not worry about what is left undone here. After all, the human experience has been sidetracked for many, many, millennia in service to others in a sense, and you have more than done your part to bring learning and healing in exchange for having to suffer at their hands. This is the great lesson for perpetrator, gifted by the victim. So you have done your share and need not feel you are abandoning your duty here in any way.