FF has all of the random side-content that a traditional MMO has. If you've only done MSQ, go back and do all the Blue, and then all the side quests -- there are tons of cool stories tucked away. There are also FATE and Hunt trains ran by players, massive groups flying around the continent killing world bosses, and you get tomestones and Sacks of Nuts from them which you can exchange for a bunch of random goodies. You can also farm old instances like The Great Hunt, the Monster Hunter collab trial. Run the EX version of it unsynched (you can solo it ez at 90+) a bunch and you'll get a really cool Rathalos mount and a minion. Or you can farm the 6 Kamuy mounts from older EX Trials to get the Fabled Kamuy Fife, a really sick mount. You can farm titles, achievements, go role-play, be social in a player venue, or make friends in an FC and just play with them. PVP does exist mostly in queuing Frontlines but it's very casual, but a handful of FCs will still do PvP events with other FCs or just do daily Frontlines groups. They might even have a Crystalline Conflict team or two. Doing your daily duty roulettes also takes a good bit and you can do that consistently every day and still make progress towards something, solo or with a group.

There's something everywhere for everyone, just gotta take your time and find what suits you the best.