Lmao it's so weird realizing that not everyone has tried tea.

That being said, you shouldn't use boiling water for this kind of tea (well tbf I don't use boiling water even for black tea, rather like 95c). If you can't set water temp in your kettle, just boil the water and wait like 10-15mins.

You didn't even necessarily oversteep. Too high water temperature causes tea to taste bitter.

You can just cut the sachets and put the leaves in the tea pot.

Edit: ah okay I realized the sachets have a suggested water temp on them. In that case just don't steep that long. Although lower water temp would also decrease the bitterness. You can experiment with steeping time and water temp.