Discuss this file
When editing a file in teams, or locating one in the search bar, it should be possible to select an option called "Discuss this file" where you could tag others in a chat.
I'm currently having to get a link to the file, start the chat, post the link into the chat.
believe this is possible.
Open the file in Teams and then in the top right there should be a "speech bubble" you can click. Would this suffice?
Note: Whole conversation can be seen by everybody in the Team and is also posted to the "main" conversation Tab.