>>57563
It goes a little deeper than that. Teen Titans got hit with that dumb rule DC placed saying only one version of the character can be active at a time (With the exception being anything DCAU related). Which is how Batman 2004 started with Batgirl before introducing Robin once Teen Titans ended. The shows were essentially stuck in an internal legal battle on which Batman characters they could use. I mean Deathstroke was changed for the censors but it created a loopole on how the character could be used.
Like the other Anon mentioned-
>>57568
-there's a lot of history regarding the DCAU but the shows were too fundamentally different to really crossover. Static was a lot more prepared for this and if Tim were to have the Titans in the DCAU he'd make his own version, probably something inspired by the 70s revival.
So that just leaves Batman 04 as the only real "legal" option for a Teen Titans crossover. The artstyle is very similar, the comedy doesn't really clash and when Batman 04 ended it had Batman joining/busy with the Justic League.
The only thing really missing is accounts by staff members talking about it. And there must've been discussions regarding the two considering the internal politics regarding characters. People love pointing to Jason as Red X, but his attitude, death and history was never going to let him be adapted. Hell, if im not wrong Jason's first animated appearance in a proper show was Young Justice. So Red X being someone close to Robin while still being legally distinct in the eyes of the censors leaves a very short list of characters. They were able to fit Jason Todd in those New Teen Titans shorts along with DCAU Alfred and Batman but those were made years after the original series. Red Xs' identity must fit within the original parameters, but of course they could always change it, its almost 20 years since the original show aired so Red X could literally be anyone at this point.