I was trying to find the chat when playing but I don’t see one. Do they not have one at the tables when playing?
I am not sure what device you play on but I play on a laptop.
Once displaying a table there are various items at the top of the page left and right (volume, settings etc) but at the bottom of the page left a large box with CHAT, NOTES, INFO headings.
It's sort of impossible to miss.
There is a constant summary of play running just like ACR (with or without anyone contributing to chat)
Go to the lobby open any game and you should be able to see it at any table immediately.
EDIT - by the by, what might confuse you in the CHAT box is you have to click on 'why not say hi to those at your table' to write a message.