On YouTube, the built-in adblocker is not working at all. And by that I mean the ads just aren’t being blocked as if I had toggled it off completely. (No “adblockers are not allowed” prompt.) This applies for both the in-video ads and home screen ads.
And just a FYI, in general need to make sure never to launch Brave as administrator.
If that’s too confusing, you could always just uninstall, making sure you choose the checkbox to delete data, such as I show at Brave doesn't start when I run it as administrator and Brave Shield doesn't work - #92 by Saoiray. If you go this route, make sure you have exported your passwords and bookmarks or you have it synced with another device so you can easily import/sync to get your passwords and all back. Otherwise it will all be lost in the uninstall.