Prerequisite reading, partially already answered on same link security-misc: Enhance Miscellaneous Security Settings.
CPUID is a mess and I don’t think there is any method to curb it.
Then then I found this cpuid x86 in JavaScript. but didn’t look into further.
Speculation: even if using security-misc: Enhance Miscellaneous Security Settings (or maybe even QEMU) it might still be possible to benchmark the browser to guess what hardware is being used and/or to fingerprint the browser. Using JavaScript. Or perhaps even without. For Tor Browser specific questions, I recommend, there is likely better information from Tor Project as per Free Support for Whonix ™.