[OS X TeX] benchmark a pdflatexmk run on a Mac Studio?

[Luis Fernando Sequeira]

> Both are with standard apps running (or sitting) in background, including a real-time antivirus scanner, TextEdit, Skim, Preview.


And that may well be your problem... 
There is no reason to have a "real-time antivirus scanner".
That is probably the cause of this enormous slowdown.

If you are under the impression that your mac is at risk otherwise, try a simple test.
Disconnect your mac from the internet, turn  off your antivirus, and typeset. 

Also, the following post by one of the most respected contributors at Apple forums can help clarifying the question of securing our macs:

https://discussions.apple.com/docs/DOC-8841 

I do not have a Mac Studio, but I don't mind trying your book on my Intel 2019 16" MBP.
I am pretty sure it will take much less than 5 minutes.

Regars

Luís Sequeira