I was an OpenBSD admin in 2002-2003, Linux admin since 2001, IBM zVM admin since 2006. I find this snap/flatpak world confusing: bind mounts, virtual directories, multiple copies of the same libraries, apt-get dist-upgrade does not upgrade vulnerable libraries because there's a copy inside a snap. It's a mess.
Looks like you have the snap version of tree, so when you run it, it runs inside its own snap container and cannot access Brave container, so it won't list anything. Looking at
https://askubuntu.com/a/1245306/800622 I see that removing the snap version and installing the apt version should work. I cannot not test because one of the first things I do on my Ubuntu installations is purging any and every snap installed, removing snapd and blocking it from installing again with sudo apt-mark hold snapd.
I like Brave but I use Vivaldi. It's made by the team that made Opera great, the Opera from before. It's Chromium based, so all extensions work the same, all sites work the same. It's light on resources and very quick, so it's my daily driver since one of the first public releases, when it was in alpha stage and I was disappointed with Firefox sluggishness and Chrome privacy-invading features. And it has an official deb build.