It could be that Brave has some settings that disallow redirecting to app to launching an app. So the login is not able to relaunch the Trakt app to complete.
Try looking into settings or check if Chrome gives you the same problem.
Thanks for getting back to me so quickly, I’ve tried another browser (duckduckgo) and got it to work, I don’t use chrome/ms edge as I run a custom ROM built for privacy and security.