If you're still interested in making notes without the use of team chat, you can use https://greasyfork.org/en/scripts/32269-private-notes-4-games
You will need to install a 'user script manager' as described on https://greasyfork.org/en/
for the script to be installed and take affect.
You need to install the script and user script manager per browser you use.
When a game loads, the script needs to read the game notes in a new tab. Don't close this tab as it may make the wrong note options appear. (This tab closes automatically.)
When you create or modify a note, a new tab is opened momentarily to allow a note to be created/modified and then saved. Don't close this tab manually, it closes automatically.