Do we know why it was cancelled? Low scores with their focus groups or something else?
reactions seemed to be reportedly okay, not thrilling but not abominable. more importantly, a new exec just came in a couple months ago and decided he could get quick cash by using it as a tax writeoff, rather than by releasing it as content to support hbomax. so he did, quickly dumped straight into the trash even though it's already nearly finished. he didn't even consult the president of DC films on the decision, who almost quit on the spot over it and started consulting lawyers. the director learned about it while traveling abroad for his wedding.
the new suit is also absolutely not a fan of lower budget projects, wants to go exclusively big event theatrical, and decided that projects like batgirl are no longer on-brand and wants them all buried.
the entire industry is shocked and appalled (by this and all the other decisions he's recently made that are presumably putting legions of people out of work) and warner stock dropped 17%
I kind of imagine he cares a lot less about it than most people do. As long as he gets paid he's probably fine - he's really not the kind of guy to get ultra invested in superhero stuff.
it's a job
as an actor I'm sure he's disappointed that all the people he worked with will not get their work seen, just as a professional and a creative surely he's not happy about that like any crew member would be
but as for any attachment to the character himself, yeah i dont imagine it's all that important to him. reportedly he didn't have too much of a presence in this movie anyway, and a more meatier return elsewhere is still on the way.