Guangzhou people usually like to drink very strong tea. Often, they pack their pots full with Yancha and TGY and use shorter brew times. To be honest, it is almost a barbarian way for me to drink tea. It's usually too strong and over the top for my tastes. But, many like this.
Bitterness is usually counteracted by lower temps and a longer brew time for many teas, especially Japanese greens. I notice with dancong that bitterness and a dryness in the mouth is often a feature even with very low temp. This is particularly common with lower grade tea.
Do you ever lower the temp and brew longer to see what you get?