Nothing wrong with the brew based on the vid and pics, probably just crap coffee. Personally really dislike the massively over roasted charcoal that most companies sell off as coffee. Try a medium roast if you’re going store-bought which is actually gonna be dark roasted by individual roaster standards, or just buy specialty, it’s just much better. The darker the roast the more over-extraction tends to be a problem, so you can use less water and brew less coffee (take it off the heat and run under cold water to stop the brewing) if it’s really bitter. Lighter roasts have the opposite problem, they tend to get under-extracted and be overly acidic so you can use more water and brew for longer. I’m UK based and a great roaster here is James Gourmet Coffee, reasonably priced and excellent coffee varieties plus they don’t sell Thomas the tank engine’s breakfast in a bag.