"VSync" is not working on second display

Hi, I’m new to EndeavourOS and I need a help please.

I have this laptop HP Pavilion Gaming 15-ec2800nc and if I connect second display, it connects to nVidia graphic card. And if I’m watching video or something, the “VSync” is not working. I don’t know how to describe it better. But if I watch the video on integrated display, all is ok. I’m using optimus-manager for it, because if I use nVidia drivers from first boot screen, all applications are lagging on second screen.

Sorry for my English. Thanks for responses

And my graphic card is nVidia Geforce GTX 1650 and DE is KDE Plasma