3,237.5 hours, Star Trek Online. I recently started playing again after a 9-year hiatus, so about 2,900 of those hours are from like a decade ago.
Btw (shameless plug), we're trying to get a STO community up and running in the verse: https://kbin.social/m/sto. Any other captains around here, feel free to drop by!
You'll dig it if you're a Trek fan, especially if you like the ships. Oh lordy, there are ships. However, it's an older game, and it's very grindy/paygate-y, if you know what I mean. The game is free to play, but it really pushes microtransactions and loot boxes. I wouldn't say it's any worse than your average MMO, though.
That said though, it's a great game if you're a Trekkie. It's set in the Prime universe, picking up several years after Spock disappears in the 2009 Abrams movie. It's still in active development, with new content coming out all the time, and several actors from past shows have done voice acting for certain storylines. And the ships, holy crap, the ships...