CoD has a VRAM issue currently and it's a walk thinking you've maxed your vram and well you haven't and tanks your frames. There's a fix for vram usage with cod 

It has a 3060ti, Ryzen 7 5800, 16GB RAM

What video card, what CPU etc... would be helpful information.

What would be the solution for that? Lowering the settings? 

maylonacosta,

It is always helpful to our users if you could list the specific Alienware Desktop model?

COD VRAM 

Since this involves editing game configuration files, ensure to make a backup of the files and there's no guarantee it will fix your issue. But it does sound like it will fix your issue.

Windows KEY + R

Put the following into the Run dialog box

C:\Users\%username%\Documents\Call of Duty Modern Warfare\players\adv_options.ini

// generated by Infinity Ward
version = 1
VideoMemoryScale = 0.85
RenderWorkerCount = 4
ConfigCloudStorageEnabled = 1

Note that numbers can vary its not a panacea,

VideoMemoryScale is the root cause of the lag spikes.
0.85 is the scaling factor for how much VRAM is going to be used when playing Warzone.

For example, RTX 3060 8GB VRAM,  VideoMemoryScale is set to 0.85,  8GB * 0.85 = 6.8GB. This means that you're capping the VRAM usage at max 6.8GB, the rest of the VRAM is not being used. Increasing the value may fix the issue.

I changed to 0.95 for my Nvidia GeForce RTX 3060 8GB card, and it seemed to work.

The default video memory scaling value was 0.85
do not recommend going all the way to 1.0

Thank you for the information. I will try this and see if this fixes the problem. However, why is it that it only happens after a while of playing and it started happening 3 days ago. Before that, it was working perfectly. 

I'm not going to support software speculate as to why.

I can only tell you from my own personal experience this is a known issue.

Its not the only issue that can cause lag but its one of the most common.