You don’t owe an instant reply to a message designed to start drama.

Some messages are not attempts to communicate, they are attempts to get a reaction, and a fast reply is the exact product being requested. Answering while stung means answering on their terms, at their speed, usually in writing that can be screenshotted. Waiting is not weakness and it is not avoidance. It means the next move is yours to choose rather than theirs to trigger.

When something lands that makes your chest tighten, put the phone face down and do one ordinary thing. Come back in an hour and decide whether a reply is needed at all.