For testing, create AN ADDITIONAL Brave Browser user Profile (Menu --> More tools --> Add profile). When creating:
Make no appearance adjustments other than to set user profile color at brave://settings/manageProfile.
Do not import anything.
Do not add any extensions.
Do not make any adjustments to content filtering at brave://settings/shields/filters.
Do not allow/enable any Brave Browser “bells and whistles” such as Brave Rewards, Brave Talk, etc.
Suggest that after you create that new user profile, Exit / Quit everything and restart the computer … and then start up Brave Browser and choose the new user profile for testing.