We know that during TLOU Online development they didn't have TLOU3 under production. TLOU Online development started in 2019 when they branched the online MP mode of TLOU2 to make it a standalone game that would be the biggest and most ambitious ND game ever.
In the recent Grounded II documentary, which later part was shooted I think April 2023, they weren't working on TLOU3. A bit later, when they cancelled TLOU Online they had two AAA SP games under development: one started around 2021 and another one around early 2023.
The 2021, started as their next big SP once they completed TLOU2. That title could be the Uncharted spinoff that Bend started to work on but they left the project to focus on the next Bend IP. This, or the 2023 title could also be a new IP.
Just after cancelling TLOU Online they could have started to work on TLOU3 to rehash most of the work they did for TLOU Online. They could put there the small Tommy story and whatever they were going to tell in TLOU Online. If didn't start to work on TLOU3 back then, they could maybe soon, because I assume part of the TLOU Online moved to support the other two teams but they'll have people free to do something else.
The main question is, when these games are going to be released? Nowadays AAA games take more than years to be released. So we're talking about at least 2027 for the first game (Uncharted or new IP?), and at least 2029 for the other two.
They can make a TLOU3 set after TLOU2 with Tommy as main character, that is basically Tommy and Ellie remembering Joel. So almost all the game would be flashbacks of portions not shown in the other games:
- Intro: Ellie cuts Abby's head with a chainsaw and throws her corpse to feed her pigs in the farm
- Flashback with Tommy: finds the new base of the Fireflies and where Abby is and goes to tell it to Ellie. Before going to take her down both rest near a bonfire remembering stories with Joel:
- Tommy + Joel: Tommy's POV of when realized about the infection
- Tommy + Joel: Struggling to become hunters and scavengers during the pandemic, having to kill other people to survive for the first time
- Ellie + Joel: some nice moments shared together and hard lessons Ellie hard to learn with Joel
- Tommy + Joel: some story in Jackson while patrolling together or having to search for some important loot
- Tommy + Ellie: take down Abby's group with her as final boss. After it they go to the Fireflies base where they learn about Ellie's parents and why this time they are sure that can make a cure beacuse someone in Europe already achieved it (and don't need to kill Ellie).
That would close Joel + Ellie's arc, but would open two more for future entries: one to tell the story of the Europeans who achieved it. Other one would be to bring the cure to Latin America and Asia.