Micro lags / stutters in every steam game

[HoeLeeSheetskins.army]

Hi. I have had a new computer for 3 months, including: RTX 4070, AMD Ryzen 5 7600 and 2x16GB RAM. However, I have a problem with micro lag in every Steam game. I will use ETS2 as an example. I have a 165hz monitor, but in the game itself I set the refresh rate to 120hz and the frame limit to 120fps, and I turned on vertical synchronization. Unfortunately, every now and then the fps increases or decreases by 2-5 minutes, approximately from 1-3 minutes, which causes the game to temporarily hang. It is not long, but visible to the eye. This happens in every Steam game, be it City Car Driving or Beam Ng Drive. To be sure, I installed Fortnite, but I don't have anything like Steam games. Can anyone help me because unfortunately it spoils the entire gaming performance

[HoeLeeSheetskins.army]

I will add that no matter what graphic settings I set in ETS2, whether low or ultra, the problem still occurs. I also deactivated the modifications, which did not help