It is clear from your post that you don't know what a Ponzi scheme is. You, as well as many others, are under the mistaken belief that a pyramid scheme, or a pump-and-dump, or even any scam is called a Ponzi scheme. Tulip bubbles, chain letters, and crypto bubbles are not Ponzi schemes.
In a Ponzi scheme, an operator pretends to invest a victim's money but does not.
Typically, in order to convince the victim that their money is really invested, the operator will return some money and claim that it is a return on the investment. However, that step is not required. In some Ponzi schemes, the operator may credit the victim's account or not allow withdrawals for an extended period of time.
So, Bitcoin cannot be a Ponzi. There is no operator. There is no investment. There is no return on investment. Recently, the term "natural ponzi" was invented to describe Bitcoin. The inventor of the term wanted to claim that Bitcoin is a Ponzi scheme but couldn't, so they invented a new term.
OTOH, Bitcoin can conceivably be described as a pyramid scheme. Many people buy bitcoins in the hope that they can convince others to buy bitcoins from them at a higher price. There is nothing wrong with that -- it is basically just speculation. But, when they claim that Bitcoin has no utility other than a "store-of-value", they are essentially promoting Bitcoin as a pyramid scheme.