The entire Titan HM fight is scripted, that itself is already fairly easy. Aside from Landslide or brink of death (not weakness), the fight is usually recoverable.

If connection is the problem, then that's not really related to the fight at all.

My internet is like average or below average (3.76 Mbps down, 0.67 Mbps up with 96 MS ping), and I've passed most contents except T5 and ifrit EX (In progress)

And that's coming from a mediocre player.