The browser was fast at the beginning, but got slower over time. Especially the initial opening of the browser takes ~5 seconds. I actually have this issue with Chrome too, it also gets slow over time.
I’m guessing reinstallation would fix, but can’t find the “export bookmarks” option anywhere so that I won’t lose my bookmarks.
Brave Version:
Version 0.68.131 Chromium: 76.0.3809.100 (Official Build) (64-bit)