Lagging/fps drop in 3340x1440 resolution.

Hello!

 I would like to ask for help because the game lags at 3440x1440 resolution. The full story: So far I have been playing on an asus full Hd (1980x1080) monitor. A few days ago I upgraded to a SAMSUNG Odyssey G5 C34G55TWWPXEN 34'' Curved WQHD 165 Hz 21:9 FreeSync VA LED monitor. It worked fine for a day or two, but then something changed. The game runs perfectly smoothly at the beginning, then from one moment to the next it simply lags. It's like I have an FPS drop, and after a few seconds it runs smoothly again. I have tried lowering the graphics or setting it to completely low, but it simply doesn't work well at this resolution. My computer has to handle it. Specification: RTX 4070 Ti Super 16gb, Ryzen 9 9900X processor, 32Gb (6000mhz) kingtosn ram. If anyone has any ideas, please help. I don't want to trash the game because of this.

Thanks in advance.