Hi Korokush,
Instead of changing the monitors refresh rate, you could cap the viewports fps to match your monitor.
In editor hit ~ (tilde) and the command is t.maxfps 60 (Random protip: set your maxfps to something low when working on a laptop for better battery life and a cooler gpu (less fan noise))
Or even better, just enable vsync in-editor with r.vsynceditor 1
Hope that helps!