"Where did physicals come from if God is non-physical?

If only non-physicals can cause non-physicals wouldn’t it follow from then that only physicals can cause physicals?"

The quantum physics revolution shot a hole through the notion of physicalism, i.e. the whole idea of substance was considered an illusion. See, for example, Sir Arthur Eddington, Sir James Jeans, Werner Heisenberg, and others.

The conclusion is that there is only non-physicality, i.e. the mental.