This is the Medium reading order of Superman Rebirth Phase 2 which is headed by Brian Michael Bendis. There are two main ideas. 1. Superman meets new threats he’s never dealt with before. 2. Superman has to learn to accept change. 3. Superman’s Side Cast gets a chance to shine (later on).
The titles:
Superman = Superman (2018)
Supergirl = Supergirl (2016)
Action Comics = Action Comics (2016)
Man of Steel = Man of Steel (2018)
Adventures of the Super Sons (2018)
Part 0: Pre-Bendis but post Phase 1
The Adventures of the Supersons
The Adventures of the Supersons #1-12
Part 1:
Man of Steel
Man of Steel #1-6
and Last story of Action Comics #1000
Superman: Phantom Earth
Superman #1-6
Action Comics: The Invisible Mafia
Action Comics #1001 - #1006
Supergirl: Killers of Krypton
Supergirl #21-26