I won't lie, this episode is intense and upsetting, but it's an important part of the dramatic tale. Ed is going through it. While the tone of season 1 was sunny and Stede-focused, alert viewers could see that Ed was prone to depression and was in an ambiguous state before meeting Stede distracted him for a while. Heartbreak has catapulted him back into his worst, most destructive self, and his crew is suffering along with anything that has the misfortune to sail nearby.
Stede is back to his singleminded focus on figuring out where Ed is by triangulating his crimes on a homemade map, and provides some semi-wise counsel to an old friend. Zheng Yi Sao, we learn, overlaps a bit with Stede's holistic view of wellbeing for her crew, but she's a much more formidable captain to be on the wrong side of.