I will like to keep this simple and short, you want to invest in DeFi projects? Yea they are the best presently in terms of fast growth and adoption but watch out for new DeFi projects because they are probably scam, you want DeFi project? Look into those that's been around since 2018 or max 2019, not all newly launched DeFi projects starts development in 2020, DYOR and Play Safe.
You're right, I can still understand backed in 2016 to 2019 when ICO, IEO and STO were onboard, the first sects of these projects went successful and later-on they fell into the hands of the scammers, who now used them for scam. Basically, this defi projects will surely take the same roots like the above and the only solution is, don't be anxious to make investment with new defi projects because they could be from scammers.