The Hero

Clear all four trials in the unmoored world - each is a big elemental dragon-type boss, marked by a red beacon over a settlement. Mind the soft clock: time only advances when you rest, and regions are destroyed one by one after enough rests, so don't sleep more than you need to. Killing all four bosses stops the clock entirely, after which you can potter about at leisure. Come in at a decent level and well-geared - these hit hard, and low-level characters can be one-shot. The Gigantus trial hands you 525361741 along the way. Get all four done before you trigger the finale at 121731681.