Introducing the new John Connor..

No need for a reboot. Just keep going with the storyline.

"new John Connor"

This sounds like just the sort of stunt casting that some producer is working on as you speak.

The pitch... "John Connor is alive! The elder John Connor we saw briefly in T2 wasn't the young version in the rest of the movie or the one killed in Dark Fate.

The elder Connor is in fact a Terminator that went rogue on Skynet (shades of GeneSys and Salvation). The best bit? His external skin is cloned from tissue samples by Cyberdyne obtained from the original T-800 as part of their program to allow robot soldiers to integrate naturally alongside biological soldiers in the field. He's the "son" of the original T-800! Is that super-meta or what? This movie will explode I tell ya'"

And Joseph Baena would make a great T-800!