An OG timeline (FO1, FO2, Tactics, and FNV) and a Bethesda timeline (all the games/shows they made). I don't know why Bethesda didn't do this when they got the rights. It would make things easier for them. Due not having fans talk about how Bethesda broke the lore. Will, if they don't broke their lore. But you got my point.
EDIT About New Vegas. Bethesda didn't make it, but they did published it. So what timeline it belongs in? The reason I put it in the OG timeline. Because it being more similar with the OG games then Bethesda ones. But the show throws an monkey wrench into things. I guess New Vegas can be in both timelines.
EDIT 2 Both timelines can have the same factions, creatures so on. But the OG games are still canon in it's timeline. So everyone can be happy.