Hi there. I’m using Brave since several months and so far allright.
I use the black theme and I notice that when I have more than three tabs, it’s hard to see which of them is active. Perhaps you could say that it’s obvious, as it’s the tab I’m watching now, but when I’m researching about a topic, all tabs are similar and it’s not so easy. For instance, when I want to close the active tab, because the content doesn’t seem very interesting to me, it’s frequent that I close another one.
The blame, of course, is on the lack of contrast between the black color on the background of the non-active tabs, and the very dark grey on the background of the active tab.