I totally understand this issue and I’ve the same issue. I’ve never taken more than 24hrs to reply. Even if the messages come around 2-3 am; I get up and reply.
But in January, I had Covid for about two weeks and I wasn’t able to reply within the first hour. But somehow I did within few hours. This made my response rate go down to 92%. Now I’m stuck there and don’t know how to improve the situation.