I cant find any settings in Brave that would allow to opt-out of it (ab)using mailto: links.
I have email client program of my preference, why would I want these links to be opened in a browser?
Whats worse, no matter how many times you change it, Brave keeps changing the setting back!
On Mac, to access default email client settings, one needs to launch the Apple Mail app.
Patterns of behavior:
Brave opened. I open Apple Mail settings, see that email client is Brave, change it. Then I click on mailto: in another browser and my choice app is opening, but only once. If I reload any page with mailto and click again, Brave will open, and on going back to settings I would see it is again default.
Brave closed. I open Apple Mail settings, see that email client is Brave, change it. Then I click on mailto: in another browser and my choice app is opening, but only until the Apple Mail is closed (and it is not my email client). After I close Apple Mail, Brave sets itself to be the default email client again (even though it was not running). So if I want to use MY CHOICE of app, I have to keep Brave closed and Apple Mail opened.
Extremely annoying and nasty behavior.