I’ve been getting such bad anxiety about reading many hadiths that mention doing a sin that will assure you a place in hell. Why are these hadiths so clear that hell is promised if Allah forgives sins? A lot do not mention that repentance is possible as well which confuses me.

Talking about hell is what we create for ourselves and Allah's doors of mercy and Forgiveness are wide open. There's no confusion, we are creating our own hell and heaven from moment to moment. Allah is a Merciful Rabb. Its us who go astray from His guidance