To be clear the tvline report is citing a spokesperson from Warner Bros directly not just unnamed sources:
TVLine: Black Canary Standalone Movie Still in Development at HBO Max
The GL report is from THR:In the wake of Warner Bros. Discovery abruptly pulling the plug on the nearly complete, Leslie Grace-starring Batgirl movie, a spokesperson for Warner Bros. Pictures confirms for TVLine that the Black Canary standalone movie that was first announced a year ago remains in development at the streamer.
DC’s ‘Strange Adventures’ Scrapped at HBO Max
EDIT: TVLine also saying the same thing re: GL per a HBO Max spokesperson.Green Lantern remains on track at the streamer, sources say, with Finn Wittrock and Jeremy Irvine set to star and Lee Toland Krieger (Superman & Lois, You) on board to direct the first two episodes. Sources say all involved are taking their time with the effects-heavy show — the priciest series Berlanti Productions has ever mounted — in order to get it right. (Berlanti co-wrote the screenplay for the 2011 Green Lantern feature film, which was panned by critics and considered a flop, grossing $219 million worldwide against a $200 million budget.)