Try this first
Change just one variable: try a slightly coarser grind, then compare with the previous cup.
Why this can help
Grind changes extraction. Side-by-side tasting tells you whether that change helped with this coffee.
What to try next
If bitterness remains, review your coffee, water and brewing method.
Related skills: Brew and dialing in. Explore the Home Barista Roadmap for more context.
Every coffee and setup behaves a little differently. Make one change, taste, and keep the result that works for you.