There are indeed many definitions of work. I'm using "something produced or accomplished by effort, exertion, or exercise of skill", https://www.merriam-webster.com/dictionary/work.

But then again, managers are very skilled at power games, and the ultimate sign of power is taking credit for what your subordinates produced.

You're working for a bad manager. I appreciate the management at my company. They keep the lights on and take care of all the stuff I would never want to do and I can concentrate on development.