Have you tried the mushroom coffee?
Its no good as a substitute for real coffee (I thot that was the purpose)
but its a good supplement and the taste is OK.
Thought about trying the mushroom coffee then realized I ought to use up all the health supplements I have first.
I have been doing coffee experiments for cheap healthy sweeteners. A dash of baking soda and/or cinnamon on the grounds prior to brewing can remove bitterness. Agave, honey and/or maple syrup are pretty interesting and effective too.