As it was mention before, those videos "shows" 16GB of RAM, most likely in dual channel configuration, any gamer knows that you want dual channel memory. Now will that fix the whole FPS issue, not soo sure, but is a start.
Also how clean your windows instalation is can also impact the FPS you are getting.
Do you run Fornite from an SSD, or a mechanical drive?, this can impact just a little bit how the game play and thus the FPS you see in the screen (honestly it will be really a small diference but its there).
Anther thing, there are ways to disable some of the security mitigations affecting intel CPUs in Windows 10, this can also lead to a few extra FPS, not many as the RAM, but just a few. I do not recommend this.
Finally, how on earth do you know for sure that the guy on the video is actually runing the game on a Core i5 9400 + RTX 2060? Im not saying hes isn't, but it could be that he is not, and using in fact a higher tier CPU and GPU.
Just because MSI Afterburner OSD is showing theoretical "i5 9400F + RTX 2060" tags does not mean he has that on the system runing the game, you can rename those tags and write whatever you want.
For instance, the following is a fake image just to prove a point: