What proportion of LEGO Technic parts are specialised in a given kit?
For the 42100 specifically:
https://www.newelementary.com/2019/12/lego-technic-review-42100-liebherr-r.html
Since links are discouraged as them being ephemeral, here's the two most relevant pictures:
New parts:

Existing parts in new color:

In the first picture, the bucket is exclusive to the set, the other parts have been re-used in a couple of smaller sets.
In the second picture, except top left and bottom right, these parts are also very new in other sets, they were introduced in the 2020 Spike Prime educational set (a set with programmable components, similar to Mindstorms)
I would say this number of new parts is fairly typical of all flagship Technic sets.