I have updated and using latest version .
I haven’t tested extensively with harware acceleration disabled but , if I disable it Netflix videos are not playing in HD, and it stutters.
Turning off hardware acceleration, will increase CPU resources. But can be less problematic when viewing videos. To decrease CPU resources, enabling hardware acceleration will help (but will increase GPU resources). It is a trade off between using additional CPU or GPU resources
May help, also tuning the output video resolution will help (maybe keep it 720p/1080p)
I think since Brave monitors user activity on tabs for rewards programme all the time and stores the log (although the data stays in the browser itself). It is bound to consume more power as compared to other browsers. How much more I cannot say.