As far as I know, the Brave Browser does not allow the Touch Bar on the MacBook Pro to be customized.
This is causing a usability issue for me. When entering text into a dialog box such as the one used to enter this specific post, there is a back button on the Brave browser touch bar that has many times activated while I am typing. The little finger or the ring finger of my left hand may accidentally brush across that back button. The result is that I lose everything that I have previously typed into that box. If the Touch bar were customizable, I could remove that back button from that location but as it is this is very frustrating.