The button with the plus sign for new tabs in the vertical tab strip of the most recent official build of Brave (with vertical tabs enabled via flags) on Windows is currently not high enough. For some reason it has less height than tabs, which makes it difficult to hit.
I don’t have hand coordination issues, but this must be awful for people how do. So this is an important accessibility and usability issue that needs to be fixed as soon as possible!
The solution would be to increase the height of the button with the plus sign for new tabs in the vertical tab strip, i.e. it should have the same height or more as tabs in the vertical tab strip.