Create a new, Linux OS user account (admin level).
Do Not copy any settings or files to that new admin account.
Restart the computer and sign on: that new admin account.
Launch Brave Browser, and Do Not import anything nor transfer any settings to the new Brave Browser profile that will be created.
Test a download, using a simple, test PDF file, courtesy of W3C:
‘https://www.w3.org/WAI/ER/tests/xhtml/testfiles/resources/pdf/dummy.pdf’