It seems like you want this to be equivalent to Dependent: "the support test is a very close call for some people" Claiming as a dependent, vs Support, vs, for instance Custody, are all different types of tests. Just like some qualifications use Earned Income and some use Taxable or Gross Income.

For instance, you might Support your parent, but that parent is not a qualifying dependent for purposes of EIP.

You have to read the regulations and follow what applies.