The Ponzi scheme can be identified by various factors, including: on the guaranteed return. As long as new investors join in, the system works. In this case, sufficient capital will be available to disburse existing investors as long as they do not withdraw and reclaim the investment.
A well-known example is BitConnect:
BitConnect promised to take Bitcoin Investing to another level and open it up to everyone. For this, the makers behind BitConnect have introduced their own Coin, the BitConnect Coin (BCC), and a few months later the BitConnect Lending platform. With the platform, it was possible to invest in automated Bitcoin trading and benefit from daily distributions.
As you can see very well in the following picture, BitConnect profits are above average (even if the return on Crypto can be higher) - 40% per month for a passive system is unrealistic.
It is very easy to see what happens when the system collapses.
The danger with this project was that many - also known - creators, influencers and Twitterers actively promoted the project and presented it as an ideal source of income. Why? Because they used their referral codes and were thus rewarded for every new user. In the end, the followers paid dearly their trust in those.
Tips:
Researched projects in which you want to invest (DYOR - do your own research) and do not trust anyone blindly, no matter who in your environment is just totally convinced of a project.
Have no unrealistic profit expectations, no one gives you money
If you do not understand a system or project, do not invest in this project.