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$ 4000 is a sufficient amount to make you profit...
you don't like coins/tokens that are too volatile? coins that have high volatility like Bitcoin are those that can give you more profits than stable ones. Or you can also buy Binance, I see bnb tokens have a chance to touch $ 1k.
I would advise leaving 2000usd in Bitcoin and another 2000 to distribute between BNB and DOT, because I see that DOT has a lot of publicity and many investors believe that it will rise a lot in price, of course I also trust the technical analysis given in Cointelegraph, they have been quite right:

If they succeed, the DOT/USDT pair will retest the all-time high at $46.80. A breakout and close above this level could start the next leg of the rally that has a target objective at $53.50 and then $57.
Source:
https://cointelegraph.com/news/price-analysis-4-9-btc-eth-bnb-xrp-ada-dot-uni-ltc-link-thetaAnd bnb is growing steeply, it might be a good time to invest to see new highs.