Coil of Bahamut drops i90 gear. You basically farm that once a week. Once you have all that gear, which WILL take time, you can go on one of the other 8 jobs, and then gear that one up for 3 months.

There is basically an infinite amount of things to do, if you already have relic+1 on every job, every primal weapon for every class, every crafting/gathering class @50 with full HQ gear.

This game is the opposite of linear.