Inspect element -> Media

brave://gpu

--use-gl=desktop --enable-features=VaapiVideoDecoder
Use these command line arguments when launching brave browser.
Better, replace the .desktop entry for brave browser in /usr/share/applications/ with this in the appropriate places (Make sure to remove the trailing %U option in the Exec line which is present by default in the .desktop file).
Exec=/usr/bin/brave-browser-stable --use-gl=desktop --enable-features=VaapiVideoDecoder
Enable these in brave://flags

Install this extension enhanced-h264ify
This is weird, idk why - (i think this is not required)
On ubuntu -
wget https://launchpad.net/\~saiarcot895/+archive/ubuntu/chromium-dev/+files/vdpau-va-driver_0.7.4-7ubuntu1\~ppa2\~20.04.1_amd64.deb -O vdpau.debthen
sudo dpkg -i vdpau.deb
Install these extensions -
Install these also on other browsers -