Based on the article it looks like it might be set in the Matt Reeves Batman universe (Robert Pattinson). Of course it will take some time to write so it could end up anywhere.
It could be a solo project, it could be Matt Reeves universe, it could be James Gunn universe.
Is this an Elseworld movie?
If so, I would not be interested in it since I found the last two Elseworld movies about a Batman villain to be terrible.
Based on the article it looks like it might be set in the Matt Reeves Batman universe (Robert Pattinson). Of course it will take some time to write so it could end up anywhere.
It could be a solo project, it could be Matt Reeves universe, it could be James Gunn universe.