Title tells it all… when I want to create a new profile (either staring by the window from the upper right-hand corner or using the “Profiles” menu item, it just flashes and nothing happens. The only profile I can create is the “guest” profile, via its dedicated button.
I have not tested this feature before, and I have just upgraded my Mac to Sonoma, ie, macOS 14.0. The problem may be related to it; I simply do not know and cannot check.
I use the latest version of Brave, ie, Version 1.58.135 Chromium: 117.0.5938.140 (Official Build) (arm64), on a Mac Book Pro, 13", M1, 2020.