I recall James Tucker saying a while back that WB was pushing for them to do a Wonder Woman movie after the first movie had released, so it looks like that's finally born fruition .Pretty Sure Wonder Woman 1984 and Gal Gadot's 2017 film is the reason they're giving another animated DTV a "shot". Since yeah DC's been pretty flimsy on really doing any non Batman/Justice League DTVs since the two for Green Lantern (to promote that movie) and when they usually do one it's either in relation to another project the studio is pushing (Suciide Squad got one due to the success of it's 2016 movie) or it's relation to another fixture (Teen Titans got DTVs only because Damian Wayne was put into the Titans group) so seems like a case of the former here. Which is fine as it allows for variety while at the same time making the executives behind these features comfrotable enough to put the money needed into the project.
I don't think Damian being on the Titans is what guaranteed a Titans movie. I think they used Damian as a vehicle for introducing their version of the Titans and then decided to do an original movie with them after JLvsTT .