Unfortunately, it is the lack of experience and the laziness of the dev team that is one of the most difficult elements of the project to check before we invest. We can check the project in terms of its probability od realization, accuracy, precision and legality, but the team's personal predispositions are the most difficult element to research. Unfortunately, with so many projects that appeared in 2017/2018, it was very easy to fall in a scam or simply a terrible dev team.

Pretty soon, initial coin offerings are going to phase out completely. I am not sure about STO though. We're already feeling that right now, as most of the startups are now focusing on IEO, IDO, DeFi and NFTs. Although that there are still some who prefer this kind of fundraising method, it's just that ICOs are not going to be a common fundraising model anymore in many years to come until it will completely phase out for sure.

Pretty sure OP meant offerings in general, meaning investing in new projects as a whole, since IEOs were not as popular in 2018 he just preferred to use the word ICO.

Now in 2021 many things have changed and we got IDOs and IFOs as well which in this bull market can give you a very good return, and that's of course if you done your research and they have at least a decent project plan and are not scams/rugs, rugs are are only problem of this bull market since DeFi tokens are very popular now which mostly have anonymous team and even though sometimes code audits could give investors some assurance, there's no guarantee the auditors did not miss something which could result in that asset going to zero in just one hour or even less.

I have to admit that now it is no longer feasible to invest in ICO, because there are so many ways to invest in new projects. I last participated
in ICO in 2019, and started choosing IEO more often to invest in new projects. But since I got to know DeFi in 2020, I have also switched investments
in DeFi, because I'm a typical person who always follows trends. Because in my opinion, if we want to be a successful person, we must be able to
follow the trends that are currently popular. Because the most important thing is investing in the technology sector, don't get left with  the trending
that is currently popular.