Lol tanking in FFXIV is a can of worms in any discussion. There's always two philosophies that people hold as tanks:
1. You're an enmity holding DPS
2. Mitigate the damage and let the healer DPS
As someone who has played both styles and been in this game since 2.0, both sides are correct. Most people seem to find option #1 to be the most fun though because the DPS mechanics and rotations are generally more entertaining than the mitigation side. Holding high amounts of mitigation and self healing opens up your healer to dishing out much more potential damage than you could if the healer isn't stupid and knows how to DPS. But unfortunately that's not always the case and more people are familiar with DPS tanking so most healers are on high alert and often spend the time to heal you regardless if you needed or were about to heal yourself. But, like everyone else (including me), you're sure to find your preferred playstyle and hold it as god honest truth whether it really is or not.
But the best OVERALL playstyle for most given situations is running Shield Oath to ramp up aggro and for trash pulls (But you can run Sword Oath if you know what you're doing), and in bosses you only get into Shield Oath when you need aggro (which is usually the start of a fight).
