Gaming PC doesn't make certain games?

As the title says, I feel like I'm doing something wrong.

My computer creates games like The Witcher 3, Grand Theft Auto V and many demanding games at the highest settings without problems (also with YouTube video on the second monitor) but with games like CoD Warzone or earlier also with Fortnite (don't play it anymore at the moment I do not know if it is still so) he always "sweats". E.g. Does not load the map quickly or in Warzone I generally have low FPS even with low settings. Now my question is: why? The processor in my computer is not good in relation to the graphics card, maybe it could be because e.g. Battle Royale games use my processor very heavily. I would appreciate help and answers.

My PC components:

Processor: Intel Core i5 7600k

Graphics card: RTX 2070

Mainboard: Gigabyte GA-Z270P-D3 So. 1151

RAM: G.Skill RipJaws V DDR4

Fan: 500 watts Be quiet! Pure Power 11

SSD: 500GB Crucial MX500

HDD: TOSHIBA DT01ACA100 (I took it from my old PC)

PS: Of course, the demanding games were always installed on the SSD

Why an Intel i5 5 generation?

Go into the 7 generation

He did

How much ram do you have

Your system should pack both games from the cpu / gpu side with the left!

16gb Ram so 2 times 8gb memory

Originally the plan was to take an i5 9600k, but the mainboard does not match it. That's why the 7600k now stops