Rachael's rumored boyfriend, Dylan O'Brien, has not made a statement on the matter yet. Rachael and his relationship hasn't even been confirmed, although holding hands at a very public event seems to be a bigger deal than becoming IG official.
Listen, cancel culture is a tricky topic. However, when you've done something to seriously hurt and offend a group of people, you should be held accountable for your words and actions.
The best way to apologize is to educate yourself and learn from past mistakes.