==== mark text message as unread ====
today | 2023-12-13

I could not find a way to mark an individual text message as unread. But you can mark a chat as unread as follows.
  * Go to the chat list.
  * Tap and hold on a chat.
  * Tap to select any other chats.
  * Tap Menu at the top.
  * Select Mark as unread