Is Legacy of Atlantis set in the same timeline as the Survivor Trilogy?
Yes. Over the last few years, the people in charge of Tomb Raider have been trying to unify the franchise’s various timelines. So Legacy of Atlantis is a sequel to the Survivor trilogy, which shows Lara’s origins, and bumps the original game (and Anniversary, the old remake) from this singular timeline. This also means that when you play Tomb Raider 2, it’s a sequel to Legacy of Atlantis now, canonically speaking. Bit weird, but luckily, you can mostly just ignore all that and enjoy the games as standalone adventures.