This is the only thing stopping me from switching to Brave. All of the Chrome mouse gesture extensions are terrible. Half of them track your activity, the other half are trojans, and none of them work reliably. Mouse gestures need to work 100% of the time. They need to be integrated into the browser to work properly, as with Vivaldi.
I need customizable mouse chord gestures also-- Vivaldi doesn’t have that, and that would get me to switch from Firefox, which does have a more-or-less working mouse gesture addon.