I used to do these things unconsciously. I’d read the message from the notification, and reply some time later on. So you’re not the only one.

But now I notice when I’m about to do it, and instead just reply when I can. If it just arrived I’ll reply now.

Only cases nowadays is when a reply requires thought and space of mind for me to reply. so I read the message and remind myself later to re read and reply.

As other mentioned before, I don’t see a point in hiding the fact that I was using my phone at this second. There’s nothing wrong or shameful about it. Sometimes you’re more available, sometimes less. If the other side is busy they’ll just reply when they can. you don’t need to hold for them.