Fairly true of Eureka and Bozja.
Deep Dungeons... they're "hard" at the upper levels, but hard in a different way. It's not as much about memorizing patterns or perfecting a rotation. It's more like "One of our party just spawned 3 monsters by hitting a luring trap and a chimera patrol will be here soon, how do we handle this?"
Though that might not be different enough, but, there's much less "memorize these boss moves and complex telegraph sequences", nor do you need to do a perfect rotation for 8+ minutes.
Blue mage is another good one, and there can be teamwork involved, but... still the same basics ultimately, unfortunately.
Since you do want combat and teamwork, I'll focus on hunts (Maybe you'll love chocobo racing, a select few people do, but it's pretty solo).
Hunts are when certain tough monsters spawn in the overworld, and people organize to run through the various field areas and kill them. Depending on the zone/expansion they're associated with the rewards vary, but you can get materia (they sell well right now even if you don't want to use them), minions, glamourable armors, mounts, and so forth from them.
For the new endwalker hunts, right now they're near impossible to solo and even when several parties take them on, there's a lot of deaths - so, always a need for rezzers. For all that said there's not much complexity to them, just a lot of chaos - most people just faceroll and get full rewards.
So, why do it? Well, for a lot of people it's a somewhat social thing as well. People organize hunt trains, which tend to occur at certain times of day - and also need a conductor, a scout, and each party a leader that can report their status back to the conductor. If you try hunting and like it, perhaps you could eventually look into filling one of those roles - it does seem to offer a sort of fulfillment for the people that do them, and of course, people are appreciate to those that take the time to organize them.
I'd offer up a hunt community but sadly it's datacenter-specific and I'm not on Light. Still, ask around in game or in any Light/Odin-specific discords you have and I bet there's plenty of people that would be glad to help you get started.