More FPS on monitor than on gaming laptop?

I recently noticed that my FPS in Fortnite is more on my 75hz 4ms monitor than on my 144hz 1-3ms gaming laptop screen. Is that because my monitor only has 75hz and the laptop has 144hz or why is that? And is that better if I play on the 144hz screen with less FPS or if I play on 75hz with 200 FPS?

Your PC is probably better and can deliver more FPS as a result

But when I play Fortnite on my laptop I have less FPS

This can also be due to the resolution, for example if your laptop has 2560x1400 and your monitor has 1920x1080 pixels

Yes, your PC is better than your laptop, the monitor hz number has nothing to do with it at first

I think he means that he connected the monitor to the laptop…

I don't have a PC, just a gaming laptop and the 75hz monitor is connected to it

Is the monitor on the laptop or on another computer?

Yes, also on the laptop

Yes

Without (adaptive) sync and frame limiter it shouldn't matter which output the frames go to.

Two options: Either your external monitor has a lower resolution than your Internet panel or you connect the laptop to a dock or charge your laptop when you are playing on the external monitor and compare the fps with the performance when the device is running on battery (the most devices then throttle the power target).

The charging cable is always on when gaming

using two monitors can decrease the fps you can fix that by pressing your left mouse button on desktop, then go to display, you should see 1/2 "1 meaning your laptop" and "2 meaning your monitor" theres the same at the corner, so press it and then press "show only 2") it will how your monitor view only which will boost your fps