Assalamu Alaikum, Can Someone Who Did Terrible Wrong Still Go to Jannah?

Salam everyone, I need help understanding something and would really value some sincere, knowledgeable advice. There was a person in my life who didn't just tease me lightly-they caused deep mental and emotional harm that left me with lasting trauma. What they did hurt me so much that I almost reached a point of despair. It's not something small that I can just forget; it truly broke me down. Right now, I don't feel able to forgive this person at all. I've tried to move forward, but letting go and forgiving feels impossible. So I'm wondering: According to Islamic teachings, will every Muslim eventually enter Jannah, even someone who caused such deep harm and never made amends? How does accountability work for this kind of oppression (zulm)? And what happens if the person who was wronged never forgives them? I'm asking because I'm really struggling to see how justice is served in a case like this, and maybe I'm overthinking it. Jazakallahu khayran for any guidance.