I am using an iPhone 14, iOS v18.7.1, Brave Browser (iOS) v1.87 (192). Private Browsing Only mode. Brave Shields UP, but JavaScript and cookies Allowed.
Not signed in to Google’s Unified Login Eco-System.
10-second skip at YouTube, is working.
cc: @Mattches - OP is using OS:iOS 26.3.1 (23D8133)
This is a known issue and appears to be an issue with Youtube and/or iOS rather than Brave itself – multiple other users have reported this and see the error reproduce (in iOS systems) in other browsers including, Safari.