Mac Pro late 2013 laggy issues

I have the 6,1 mac pro that is acting up. The issue began about a year ago, and I literally tried everything software wise I could think of to no avail. The CPU overloads easily and the mac pro feels like a 20 year old Pentium 6, gets super laggy when multiple apps are open such as Chrome, Zoom, etc, nothing fancy even. Then USB keyboard and mouse stops working. AHT reveals nothing, but the Geekbench CPU scores are way below normal, like 450/550 when it should be 750/3000 for single/multi core. OpenCL score seems ok.

Please don't suggest resetting NVRAM and SMC because I must have done that like a hundred times. I went to the Apple store and all they did was wipe the drive, which was somewhat ok for a while but the problem persists. I did have memory failure too but I replaced it. I also think that heat was an issue too, because I did play games on it for a while and it got really hot. I feel like it's either a bad CPU or something, but not sure. I'm thinking, is it just time to move on, or is there a solution? Help!