FPS drops in the game despite good PC?

My problem is that I have plenty of FPS Drops, not bad, but with my 144hz monitor, even 70-80 FPS feel like laggs. In the task manager is only indicated during the play that approximately 20% of the performance of my hardware is used. Why is that so why do not they just use 60% of their power for it stays at 144FPS

I have a Ryzen 7 2700x & a RTX 2070 with 16GB DDR4 Ram.

The game is Fortnite (but Competetive if anyone can do something with it)

Have already scanned for viruses and used Ccleaner.

At which resolution?

There should be an option in the graphics settings of the game that will allow you to set the FPS.

You may need to turn off Vsync. (To use VSync anyway, since you do not have a GSync monitor, you need to change the VSync FPS cap, wherever that is defined.)