I have seen a lot of projects come and go in the Defi space. I have a slightly different take on the subject.
I have a few observations to make: If a project offers a very high APY then yes it seems walking the path of doom.
However if a project offers a low or zero APY is this a safer investment?
Not really in my . The DeFi space is like a sea full of small fish. At times most of these projects are clones of the popular projects and there is little difference in them.
So I feel it is important to see beyond the APY
Look for the purpose of the project and the token.
Read the whitepaper and see the use case.
Does the use case makes sense? How is this token going to make a difference in the crypto space and what is its unique use case.
Go through the tokonomics and see if it makes sense.
Next Check if the team is available and ready to answer your questions.
If they do then match them with the ones provided in the white paper. A lot of times the so called small project are willing to launch a project but have no whitepaper in place.

At times these white papers and tokenomics get outsourced and the team has no clue as to what it says. So be vary of such projects.
Another thing is the project roadmap. Is it going to a plan and is the team willing to share the development with the community?
These are all very important questions to be answered. Though boring one may say dear @crypto.piotr I look for these answers and a lot more before I want to put my hard earned money into any project.
Then comes the APY for sure or lack of it.