I tried what you said, maybe I was doing it wrong but all I got was Conflicting command and command not found, so what I did was delete Brave, restarted the computer and then in Terminal I used...
sudo apt install apt-transport-https curl
sudo curl -fsSLo /usr/share/keyrings/brave-browser-archive-keyring.gpg https://brave-browser-apt-release.s3.brave.com/brave-browser-archive-keyring.gpg
echo "deb [signed-by=/usr/share/keyrings/brave-browser-archive-keyring.gpg arch=amd64] https://brave-browser-apt-release.s3.brave.com/ stable main"|sudo tee /etc/apt/sources.list.d/brave-browser-release.list
sudo apt update
sudo apt install brave-browser
Now everything is working as it should and Brave is the default browser. I don't understand most of it and probably never will but..
Thank you for all the time and help in getting this corrected, hopefully this might help others.