as for me, a lot scams we have faced during ico times, and now the situation repeated with defi. but still there are a lot of possibilities to get profit, so 1) diversify you invest pocket 2) make your own research before invest. i try to choose interesting dex projects with credible founders - at least they really need token inside platform ))
besides good dex projects with high liquidity are potentially interesting for trading and long term investing
some good dex projects i saw based on Curve exchange - for example, stablecoin dex - xsigma, i'm interested because they are backed by a public company