The read receipt is the worst invention in messaging, because it turns an absence into an event.
Most of the time it is 1 of 3 things, and they need completely different responses.
Free to try. We never store your chats.
The most common one, and the one nobody believes when they are in it. Opened at a red light, meant to answer properly, then the day ate it.
The tell: it is not part of a pattern. Nothing else has changed.
Your message asked something real and the honest answer is complicated. Silence here is not rejection, it is drafting.
The tell: your last message was heavy, or it asked for a decision.
This is the one people fear, and it is the least common of the 3. It also almost never arrives alone — it comes with other changes in the same period.
The tell: it is new for them, and it is not the only thing that is new.
If it has been hours: nothing. The thing you send in hour 4 is the one you would delete in hour 9.
If it has been days and the last message was yours: 1 short, easy message that does not reference the silence. Not "did you see my text". Something they can answer in 6 words.
If it has been days and it is part of a pattern: the read is real, and the move is not another message.
Waiting exactly as long as they did is not a strategy, it is scorekeeping, and the other person can feel it.
How long to wait depends on what is open between you, not on a number of days.
Paste the thread and it tells you which of the 3 this looks like, and whether to send now, wait, or leave it.
If it says hold off, it will still write the message for you. It just tells you first.
Try it on your conversation