Research, my Maskripping colleague!
There are only two things called "Gotham Knights" in the DC product line.
The first one is a comic book series that ran from 2000-2006 and for most of its run, it was written by Devin Grayson, the first female to write an ongoing Batman title. It was about "the exploits of Batman and his extended family, such as Alfred Pennyworth, Batgirl, Nightwing, Robin, Oracle, and Catwoman" and the latter part of the run focused more on Batman's enemies (e.g. Mr Freeze). It was pretty highly acclaimed. I doubt that has much to do with this upcoming TV show or the Deadline article would have mentioned the comic specifically, and Devin Grayson, rather than hearkening back to the old chestnuts Bob Kane and Bill Finger.
The second one is a video game which hasn't come out yet, but will be released in 2022. I'm guessing that's what the show is about, too - it's a tie-in into selling the video game at the same time. The story of the video game is that it "takes place in a period of decline for Gotham City, after Batman's apparent death. Dark Knight's former partners - Nightwing, Batgirl, Robin, and Red Hood - who have gone their separate ways, but must work together once more to restore justice to Gotham and prevent it from descending into chaos. At some point, the heroes will come into conflict with the Court of Owls, a secret criminal society that is as old as Gotham itself, and their legion of brainwashed assassins called Talons, while also investigating Batman's death."
But the video game looks like it presents those four Batman protege characters in their classic comic book appearances.
Batgirl's costume is quite tight and attractive (not the Burnside version, thankfully I think that's come and gone).

- Gotham_Knights_Cover.jpg (162.24 KiB) Viewed 1940 times
Yet I find it hard to believe that a team as progressive-minded as the Batwoman writers' lineup (considering what they programmed for three seasons on the CW) is going to limit their major characters to the obvious lack of diversity seen above. So I think if they cast for character diversity, and add extra characters to the core four (Spoiler, Cassandra Cain, Batwing, Signal, etc) that bodes well for Batgirl1969's chances of at least seeing some fleeting lesbian action...maybe?
However, there's one line in that Deadline article that throws me off:
"In the wake of Bruce Wayne’s murder, his rebellious adopted son forges an unlikely alliance with the children of Batman’s enemies when they are all framed for killing the Caped Crusader." I'm thinking this means that the four core Batman characters listed above ally with the "children of enemies" against the Court of Owls, but who exactly are these children? I mean, are we going to see Duela Dent, Ethan Cobblepot, or Joker's Daughter? (who isn't really Joker's actual daughter anyway). What other "children of enemies" are there? (I can't think of any.) Or will they just make them up from whole cloth for this series?