Hello lucassith!
This problem has a lot in common with my problem described in the message:
“Help! “Show in folder” not working properly on Linux Mint 19 (Ubuntu 18.04)](Help! "Show in folder" not working properly on Linux Mint 19 (Ubuntu 18.04))”
When I click on the button you say works fine, it works fine for me. When I click on the “show in folder” button specific to each file, Brave tries (and fails) to open the file itself as if it was a folder: I get an error message window saying that the file is not a folder…
Clearly there is a bug in brave with opening the correct file manager for a given file.
Let us hope a developper is listening…
Regards,
Guy