My main suggestion is to not overthink it. If it's an obvious hiding spot, it probably is. If there's not much to hide behind, probably don't have to go there until the NPC is way past. Every turnaround spot is scripted. It also helps to be moving faster. The stealthiest you can possibly be is while riding a motorcycle, idling behind rocks and trees each time they turn around.

As for it not being fun to begin with, 100% agree. It's incredibly silly. FFXIV is never going to be a stealth game.