My "guess".
Ray was very upset with the way the upstart replacement Whedon team and WB treated the veteran Snyder team and cast. Whedon bullied and was gross and crass...unprofessional in Ray's opinion.
WB walked back any plans for a Cyborg feature. Maybe broke a contract-or at least Ray feels they did? But usually studios have provisions and stipulations and don't "have to" do a sequel any future projects but the talent IS obligated. There is no doubt some money either way but not the big payday a feature would promise.
I "personally" don't see a stand alone Cyborg feature or how that would actually work or be received. Cyborg used in JL and future "team-ups" without a doubt. Cyborg alone... Heavy lift IMO.
Maybe someone has a great idea for the project and it will move forward. I hope so for Ray. Maybe a MS on HBOMax?
Again, IF there IS more to this story and allegations, all bets are off...