Sure, let me try to explain my personal point of view of a person without any formal relationship to economic theory.
I would say that the value is created when a product is produced or, to be more pragmatic, in line with capitalist views and avoiding Marxist pitfalls, when a company sells it. So, the value is the difference between sells and costs, i.e., earnings. Not because the company makes profit, which is nice, but because they add value to the society/economy, which can be quantified this way.
The stock’s price, on the other hand, is an estimation/projection/expectation of future earnings. When the stock’s price goes up, there is no extra value created (yet), these are projections that are changing. Similarly, when the price goes down, the value is not destroyed, because it’s not even created yet. This is a change of projections, an expectation that the value created in the future is going to be lower than projected before.
If you buy a stock and sell it with a profit, this creates value for you personally, but not for the society/economy.
Market capitalization of a company is a very useful, but a fictional parameter. Nothing wrong about it, but you can’t realize this value in a transaction. Try to sell 5% of Tesla, see what is going to happen.
Now, a CEO of a company that pisses off their customer base does destroy value in the sense of intangible assets, but not the one that I mean. Also, market capitalization can change for very different reasons not even related to the company, i.e. change of discount rate.