Check in my bios is to see if the bios has any Power Limit set, which if it were enabled might cause the CPU to significantly drop performance.
I would also suggest to download CapFrameX and do a long test (600 seconds which is 10 min) in that benchmark map you made the screenshots in. Then post screenshots of the analysis screen as shown.
I don't think formatting would make things worse and it would give you a fresh start. Most of the fixes I've seen online simply don't work in my testing (hags made it worse, all the user.cfg things I've read made it worse, direct x 12 forcing made it much worse, disabling certain cores, all made it run worse), except for if you use a frame cap, use rtss async cap instead of the ingame or control panel frame caps.
Maybe memory related? I would test the memory with MemTest86. You will need a usb stick to make the test stick.
https://www.memtest86.com/
This video is a tutorial on it.
https://www.youtube.com/watch?v=3KrFkqFzIfw
I would consider also upgrading memory to double the capacity even if the test is clear. I would look for 2x16gb DDR4-3600 CL16 (which would be faster than your existing sticks, which are already very quick). Kingston Fury KF436C16RB1AK2/32 would be perfect if you could find it. G.Skill Ripjaws F4-3600C16D-32GVKC & Trident Z Neo F4-3600C16D-32GTZNC and F4-3600C16D-32GTZRC are probably also available for purchase these days that are also very quick 32gb kits.
But I can understand if you wouldn't want to spend money and it probably isn't the issue.
