we need a "reaction" that is simply "acknowledge read"

seriously.  that's what most people use reactions for anyway.  when you don't want to say anything you heart or thumb up or whatever - but really what you are trying to say is "read acknowledged"

then the person on other side be like "wow everybody loves me !" no they don't ...

let's make it explicit.

when somebody "acknowledges a read" instead of an emoji you should get a mini version of their avatar appear on the bottom.  that way you can see who has read your post.  kind of like how we have icons for the relays on the bottom of the note ( in some clients ).