Brave's StandaloneSilentSetup.exe has reported problems with unattended setup.
Instead of installing Brave for all users, it wants to live under your LocalAppData folder. Post-Setup runs as the SYSTEM user account (not you).
Try moving SilentSetup.exe to the User - Execution queue (bottom half of Post-Setup window).
This schedules it to run after you're logged into Windows the first time. The downside is Brave will be installed for just your account.
I noticed the parameter setting is empty. I am curious to know what the setting is for that
BraveBrowserSetup.exe /silent /install