Terminator: Dark Fate almost did not feature Arnold Schwarzenegger’s T-800, which would have led to a better Terminator movie. Following Terminator: Genisys’ failed reboot, which made the Terminator chronology even more confusing, the Terminator franchise returned to the big screen with Dark Fate. Promising to ignore every subsequent film after Terminator 2: Judgment Day, Dark Fate seemed like it would bring the franchise back to basics and rescue the Terminator IP.

https://screenrant.com/terminator-dark-fate-better-no-schwarzenegger-t800-reason/