Whilst much of the acting is good, the plot is tired, predictable and boring.
The storyline shoehorned the old gang back together whilst trying too hard to create another timeline and franchise.
There is almost no explanation as to why, when John is killed, the Arnie terminator doesn't disappear in a puff of logic or why an entire new timeline springs forth with the same technology and a new hero.
Tries too hard to be clever and instead fails to be smart.