Yeah, that Forbes was written on Jan. 17th 2018 so a bit dated. My mind went to thinking 2018 was this year when initially read through it after inputting into google search to only give me articles from past month. Ugh.
However, I'm still curious if there's a source definitely stating the Flashpoint movie is kaput? So much seems to go back/forth it makes me uncertain. If WB wanted, I think Cavil and Affleck would be willing to show up for part of 1 movie to soft reboot a new reality into being. If this is done though, said alternate reality perhaps should already be established I think to avoid reboot after reboot.
In all probability it most likely be a hard reboot as you say. WB's plans keep changing so hard for me to keep track.
This could be a big key movie though for WB, the sooner they get it off the ground the better as far as soft reboot goes but at the same time perhaps best they don't make a move if they're not ready to. 2022 seems like the earliest this could happen at this point; I can't see Warners releasing 4 live action films in 2021... Eitherway, I think introduction of a multiverse at some point I think is a must.