Sorry, just found this unsent in my drafts:
Deleting the message would make sense. I tried it, it works. I suppose I didn’t think of it because it is not in the leftwards-swipe or edit-message menu. Thanks.
I made a feature request for the read receipt phrasing.
The vertical centering in the avatars in QR codes is most conspicuous; in chat I think they’re good enough. EDIT: I think the centering is fine now
I am am not worried if things take a long time, especially when they are so minor I’m not sure I’d bother fixing them.