For a traditional Italian espresso, about 7g of coffee beans are extracted. For a third-wave double espresso, it's usually 18g or more.
In my opinion, 10x7g is a lot. 2x12g is more than enough for me.
That's a bit over the recommended limit of 400mg a day the Mayo Clinic, FDA, etc. recommend. Not sure it it qualifies as 'enormous' or not.
I feel this is more precise than the ml cup measuremnts, but if you wanted to be really precise, you'd have to specify the type of beans used (the caffeine content varies widely) and even the brewing method https://oldchicagocoffee.com/coffee-bean-caffeine-content-by....
And - there is an influence - even in the region the beans are grown. In the link I provided they even go so far as to differentiate as to genetics of the beans.