This is hilarious in my opinion, you are listing custodial exchanges as investment site, when you will not have total control of your funds, while you do not have the private key to your coins. I will not advice this, people can use such exchanges to buy, but noncustododial wallet like especially hardware wallets are needed needed for holding which is the investment I believe is better when the market prices of cryptocurrencies have fallen.
Honestly, yeah might as well just pour money into HYIPs that way you know there's someone there managing it and if you're lucky enough to attract more people than you're getting their money and exiting before it collapses.
Not that I'm condoning ponzis but most of these centralized investment sites are ponzis if you strip away all of their pretenses.