If you want to invest for the long term in cryptocurrency, then you have to invest in a popular cryptocurrency (has a high trading volume), because it is definitely safe and the price will continue to increase in the long term, so you will definitely get a big profit in the future and I recommend you to invest in ETH, BNB and DOT, because I believe ETH, BNB and DOT are very popular investments at any time and the price will definitely increase very high in the future.
That is ONE aspect to consider,,, but just doing that alone gets you in trouble because especially these days you have new exchanges (and many old ones) running bots of their own to fake trading volume. Just buy 10 BTC worth of ABC coin and sell/buy to yourself and volume is done easy.
Same as on defi, you can even just open your own pool and trade to it as much as you want.