Hi all, I have a problem with random FPS lag from out of nowhere.

I have a custom built computer I've had for 4 or 5 years now with these specs:

Motherboard: MPG Z390 Gaming Pro Carbon
CPU: i7-8700
Ram: 16Gb Corsair Vengeance
PSU: Thermaltake Toughpower iRGB 850W
GPU: RX580 first, now RTX 2060 KO Ultra

Now, I generally play mostly Overwatch 2 and the RX580 handled it easily. Never a drop in frame rate. One day it works fine, the next day it starts lagging like crazy. I used to play Spider-Man and Nier Automata at over 60fps (can't tell how many due to monitor being limited) but now they run at ~42fps even on a 2060. Nier Automata would sometimes lag at my settings on the RX580 when the screen was busy but not like this. I've tried all these things to fix it.

1. Checked task manager for services hogging resources
2. Lowered settings (knew it wouldn't be that but I got same FPS lag)
3. Ran Malwarebytes (I have Premium and Windows Defender. Nothing found).
4. Reinstalled Overwatch 2
5. Ran DDU, Reinstalled GPU drivers
6. Check CPU temps
7. Bought a new GPU since it was time anyway.
8. Ran DDU in safe mode, installed NVidia drivers
9. Reset windows 11
10. Enabled XMP and bought more ram because I just wanna pay the problem away.
11. Tried another PCIe port.

I'm now running on a new graphics card, 32gb of ram, a fresh install of Windows and I still have this insane lag. Any help would be appreciated.

My UserBenchmark report is here: https://www.userbenchmark.com/UserRun/58793604

Thank you for your time.