I use Brave too but I use TOR Browser when I open .onion sites. You can turn on .Onion sites in Brave if you want to. Put the following in your address bar

brave://settings/?search=onion

Turn on these two settings:

Private window with Tor

Automatically redirect .onion sites

and then click the .onion link and it should open:

http://trutube54vqa3baer2kc7aggfc5qstxkgcmzm4qxxzfaxdsihu3znzid.onion/

Because you have to open it in a "Open link in private window with Tor". Anything with a top level domain of "onion" is meant for TOR (The Onion Router). It loaded for me.