I have the problem with Fortnite that I have more jerks / lags when playing with 144 FPS instead of 60.
What could that be?
Install FPS limiter.
and how about your internet?
Which graphics card and resolution?
GTX 1060 6GB 1920x1440p
10-20 ping
Because the drop in the FPS can be correspondingly large.
For example, if you set the frames to 45 or 60, but your system does. Min always creates 100, you notice accordingly no break-in.