How can I disable Intel Turboboost and Hyper-Threading?
I found a way to do this. It does result in a 40% performance drop.

Apple has documentation that disables Hyper-Threading with the following:
Boot into macOS Recovery
In Terminal: nvram boot-args="cwae=2" and nvram SMTDisable=%01
Click  and Restart.

To revert this, reset the NVRAM.

Here is the official documentation: https://support.apple.com/en-gb/HT210108