That’s not to say that removing John Connor from the Terminator franchise board doesn’t make sense. In fact, it totally does, as once Skynet is removed from the timeline, John wouldn’t be seen as a threat anymore. Once that particular wrinkle was ironed out of history, there not only shouldn’t have been any sort of harm visited upon John Connor, but technically, the T-800s sent back in time shouldn’t have existed either.
Article source: https://www.cinemablend.com/news/2483839/terminator-dark-fate-lets-talk-out-what-happened-to-john-connor