Timestamp (date in channel or chat)
The date that separated the messages (e.g. Today, Yesterday, MM DD YYYY) in channel is quite hard to see. Please provide an option to make the date format as bold or larger font size. It should be very easy to detect this date when scrolling quickly in chat or teams message.
Yes, the date and last read separator is visually difficult to see. I have a couple channels which recieve messages overnight from an automated process and when reviewing them in the morning it is easy to scroll right past the date separator. My suggestion is to left justify the text (instead of centered), increase the font size and have the line about four or five times thicker.