I'm not expecting any kind of reboot, honestly. The way the DCEU left Cavill's Superman, he's essentially reborn already. Even if WB wanted to start over with the character, I doubt the origin would be redone again. So either way we're likely to see a Superman story that is separated from his early days and includes a new villain who isn't Zod or Luthor.
The only substantive differences I can see between a Superman following the natural trajectory of Cavill's incarnation (accepted by the public, member of the JL, in love with Lois, reporter at the DP, confident, self-assured, at peace) and a new version of the character (accepted by the public, member of the JL, reporter at the DP, confident, self-assured, at peace) would be his relationship with Lois and the status of the Kents.
One of the two elements potentially worth rebooting at this stage would be the secret identity or triangle-for-two, which would have to be resolved anyway by the end of the recast/rebooted film because that trope has an expiration date on its value to the story. WB might want to have both Kents alive or both Kents dead in a reboot. Anything else? Superman's personality, his job, his friends, his relationship with the public, and so on is already covered by the way things settled in JL.
I guess what I'm trying to say is that when Snyder wrapped up his hero's journey for Superman in the DCEU, he left him in such a way that almost anything could happen next and it would fit. If Cavill is to continue, then there's no need for soft or hard reboots. All that needs to be done is to keep telling the same story. Superman is alive. Superman is beloved and trusted. Superman is happy and confident. Superman has a mother, a partner/fiance?, a job, a boss, and superfriends. That's all you need to move forward.