It would be good to receive notifications in the top bar if new messages appear in chat that i read.
New messages are indicated in the list of channels to the left. There will be a number indicating the number of unread messages in that channel.
correct but it would be good to be notified if i'm not in the chat section
Probably wouldn't help. The scrollback for when you re-join chat is not very long, so by the time you made it there, the message would probably be gone anyway.
your suggestion doesn't work for mobile viewi don't have channel list opened there