For a while, it was extra-creepy whenever I did a semiannual log in, because pop-ups would appear, and in a very distinctive "Audrey II" voice, scream "FEED ME [your data], SEYMOUR!" But the last time I tried it, I didn't see that. Can't tell whether they gave up, or already got the data from other people and just don't need me any more.
Delete your history, starting from the oldest thing you can see. Un-like everything you liked. Un-tag everything you are tagged in. Remove your photos. Replace profile pic with a public domain image. When you finally get to zero, log out and delete all cookies and block all bugs and trackers. Then start increasing the time between log-ins. When you get the nag e-mails to come back, go on just long enough to turn off nag e-mails. Wean yourself off until you don't care about being on Facebook any more.
Then you can use Facebook on infrequent occasions, to tell all your still-trapped friends about all the other ways to contact you that have lower latency, better signal-to-noise ratio, and more privacy. If you just delete, that leaves a you-shaped hole in Facebook that the company could fill with a placeholder. Your character might become an NPC that the game-master could control to manipulate the other players.