This issue seems to be easily searchable so perhaps you have found a solution. I saw a couple:
https://forums.macrumors.com/threads/can-you-disable-cpu-cores-in-osx.1698844/
https://www.whatroute.net/cpusetter.html
In both cases, you can limit the CPU's used, not disable a specific CPU. If you don't already have Xcode, you might want to try the CPUsetter program since the Xcode download is over 5GB - but Xcode is from a trusted source - I haven't tried CPUsetter. Xcode now looks different that what is in the thread linked above but the functionality is still there. You can also try disabling hyperthreading to see if that makes a difference. You lose maybe 15-20% performance in situations where hyperthreading would have been invoked.
In terminal, type in the command:
sudo nvram SMT=0 (to re-enable, do sudo nvram -d SMT). The computer has to be re-booted for this to take effect.
In your kernel panic (or other) report, if there is a specific program that is consistently triggering the crash, it might be the program unless the program is one that is known to run multiple threads simultaneously, such as HandBrake.
You might also want to try running in safe mode.
https://support.apple.com/en-us/HT201262