A lot of things are indicating Wally will be the Flash in the Stargirl show, which is not the same continuity as Titans. It's the same situation as Vic being in Doom Patrol, the only chance for team-ups is crossovers. Kinda unfortunate, but also prevents the Titans show from being too overwhelmed in characters, while also giving each character their time to shine. Roy is kinda the outlier when it comes to the Fab Five and core Titans in general right now, since his only big appearances are in Arrow which is ending next season, and there's nothing lined up for the DCU service yet either.
The DCU service is also up in the air, since the only new content we know is coming is the rest of YJ: Outsiders, the Harley Quinn animated series, Stargirl, Titans S2, and Doom Patrol S2. Nothing else has been greenlit, and most rumours are pointing to the service being assimilated into whatever the Time Warner streaming service looks like. So for all we know, our only live-action Nightwing content for the foreseeable future may only last for however long he actually is Nightwing in Titans S2 (maybe the back half of the season, maybe the last 5 minutes of the finale, who knows). Here's hoping for more though, since Titans is seemingly the DCU's most popular show (while being their cheapest to produce) and has done pretty well for Netflix as well, apparently.