The best currency to invest will be ETH as long as you get a low price in the market, so you take advantage of selling it in the future, what other currency do you have in mind to invest?
I usually see this type of thing on Telegram channels, people who offer you things and I ask you for something in return, an amount in eth for example, one directly knows that this is a scam, what you have to do is block that user, It is the best