Titans on DC Universe has gotten off to a slow start, mostly because the Titans still weren't together after the 3rd episode, but thanks to episode 4, 'Doom Patrol', Robin, Raven, Beast Boy, and Starfire are finally united. It may have taken 25% of the season to get here, but now, hopefully, the assembled team can actually start bringing the disparate plot threads together by forming the Titans team, which is what fans are watching the show for in the first place.
It's understandable that it would take some time for the team to come together. After all, each member needs to get their own introduction, have their backstory spelled out, and establish motivations that lead them together to unite around a common cause. Titans certainly took the slow-burn approach on this front, sending multiple characters on their own side-quests before they ever even come together, extending the time before the team is actually formed. While this approach wouldn't be so jarring in a movie, or if the episodes were all released at once and it could be binged, but by now, fans have dedicated a month of watching the show 45 minutes at a time for several hours, making the drawn-out introduction to the show feel even more lagging.
Fortunately, not all that time is wasted. Dick Grayson and Rachel Roth both come together in the first episode and follow the plot line that the other characters eventually loop into. Keeping the characters separate means splitting screen time, too, though, so while Robin and Raven get their time to develop and Starfire's search for her true identity also gets a focus, Gar, A.K.A. Beast Boy only appears for a few seconds at a time, skipping out entirely on the second episode.
This gets rectified in 'Doom Patrol', where Gar finally gets a proper origin, featuring the Chief saving him from a dangerous infection in the Congo, also giving him the ability to "unzip" and rearrange his DNA in the process. Gar goes to live with the Chief in a remote mansion along with the Doom Patrol, comprised of Robotman, Elasti-Woman, and Negative Man. Rachel and Gar first meet by complete chance at the arcade where they quickly develop a connection, only for Dick and Starfire to rip her away to go back to the convent. Unfortunately, the nuns don't have the best of intentions and try to lock her away in the basement, triggering her powers and causing an explosion. When she flees the scene, she encounters Gar, who takes her home to the Doom Patrol.
This is where Robin and Starfire eventually track her down, arriving just in time to calm Rachel down after her powers flare up when the Chief tries to perform a procedure to "cure" her. The Doom Patrol's inclusion is obviously as a setup for their own upcoming DC Universe series, but also because Beast Boy's origin in the comics as part of the Doom Patrol, so having him live there is very much keeping true to the canon. While his home is with that team, Robot Man, Negative Man, and Elasti-Woman know there's more out there for him, urging him to leave with Robin, Starfire, and Raven.
The name Titans has yet to be uttered, Robin is still the only one with a costume, and we don't yet know who the big bad is, but all four of the Titans are finally in the same vehicle, meaning, hopefully, the show is just beginning. Hopefully, the rest of the show can now focus on the team coming together and expanding the plot surrounding the shadowy groups chasing Raven instead of the road trips and origins stories that made up the first 3 episodes.