Unfortunately, you're correct. Remember the Framers knew precisely what the purpose of the Establishment Clause was, based on personal experience. therefor the people, sharing the same experience with them clearly understood it.
Here are the first two Sections of a new Freedom of Religion Amendment that I'd propose, it it were possible:
Section 1: Congress shall make no law about or relating to the establishment, expansion, or prohibition of religion, or limiting the free exercise, thereof.
Section 2 The right of the citizens of the United States to freely worship God in any way they shall desire, being necessary for them in order to create and maintain a Moral and civil society shall not be abridged by Congress, the President, The Courts, State Legislatures or the State Courts, local Governments, or any elected or appointed official, thereof.
The "about or relating to" is what the word "respecting" meant when the Bill of Rights was written.
I'm ashamed of the fact that we've lost the other meanings of words. That's what happens when we stop leaning our native language, and using it as it was meant to be used.
There are additional sections to the Amendment, but these two apply perfectly to this article.