PC Problems with no way to fix.

(There should be a pic of my specs and if there isnt check the comments)

I built my pc back in 2021 for a birthday present and ive since added a new part or two, ive run into a huge problem since early December 2023, (the only reason i know that is because this problem occurred after fortnite og season). after the update Every game i have runs at such low frames and horrible spikes, the only two parts ive replaced were my video card and changed over a ssd from a hdd, i did set the ssd for the bootup after resetting it. the only thing i know about the problem is resetting my pc doesnt fix it, i reset twice before getting the ssd and the problem stayed. looking for any kind of help that might be able to fix it. open to any suggestions.