Vocabulary – Word for Entering a Room Suddenly and Fast

The same Merriam-Webster link provides the answer further down.

At present sense 4 is found in print chiefly in letters to the editor and other informal prose, not in serious intellectual writing. The controversy over sense 4 has apparently reduced the frequency of use of sense 3.

It's actually defined as a noun in the OED (at least the British English version):

noun [ mass noun ]

1 the quality of being characterized by vigorous activity and progress: the dynamism and strength of the economy.

• the quality of being dynamic and positive in attitude: he was known for his dynamism and strong views.

So, in your example, you could say "the level of dynamism in the system" or "the system's level of dynamism."