How to disable vsync right way in QML

Question

I've found only one way to disable vsync in QML that works, but animations were too fast

QSurfaceFormat format;
format.setSwapInterval(0);
QSurfaceFormat::setDefaultFormat(format);

I think, i found the way to disable vsyc using environment variables, but i don't remember how.

With vsync the speed of animations is normal, as expected. But with a mouse dragging there is a laaaarge latancy: https://youtu.be/xSpdCfFBSyo

Without vsync the speed is too fast, idk why. But with a mouse dragging it works like i wanted - with no latancy: https://youtu.be/i5xuOztnrhs