I would choose the bug report category, but as it happens, there is no bug report category in this forum, notwithstanding that there are dozens of available categories.
A prior issue was reported in which Brave cannot detect its own light/dark mode setting. Some say this bug is solved by changing the fingerprinting level, but this is false.
On Linux kernel 5.15.0-73, Mint distribution running XFCE, also on six other machines running different operating systems and versions, none of them recognize the user’s dark mode setting. Entering the setup dialog and cycling the dark mode setting (select light, select dark again) restores the user’s desired mode, but on a restart, this fails again.
The most recent Brave version that does not show this symptom is 1.51.106. All newer versions show the symptom.