IMO
1.) Terminator the Sarah Connor Chronicles (2008 - 2009), technically a TV series but the best of the lot
2.) Terminator 3: Rise of the Machines (2003)
3.) Terminator Salvation (2009)
4.) Terminator Genisys (2015)
5.) Terminator: Dark Fate (2019), the worst of the lot by far
The last two sequels are really nothing more than inferior retreads/reboots of the first Terminator movie. They aren't worthy of the term sequel.