Separation of church and state is not in the Constitution. The closest you will get is the first amendment, which prevents Congress from establishing a religion, or preventing the free practice of one.
I’m with you that religion should not be forced in schools, but you can’t use the Constitution to prevent this particular issue.
My understanding is that it is working much better now than a few months ago. I haven’t actually put it to the test yet, but it is on my list of things to try once I have time to set up my index again.