I do not believe Einstein believed God caused the "Steady State Universe."Categorically false, as he said he believed in "Spinoza's God", which is more of a pantheistic/panentheistic approach. However, where he was wrong was with his belief if the Steady-State Theory, which he believed God caused as such.
The concept of "Spinoza's God" probably is closest to:
Spinoza on God, Affects, and the Nature of Sorrow - Florida Philosophical Review
Rocco A. Astore, The New School for Social Research I. Introduction Throughout the history of philosophy, many theorists have attempted to explain the meaning and cause of people’s sorrows. One philosopher, Spinoza, claimed that everything ultimately follows from God and that sadness is a...
cah.ucf.edu
Spinoza on the Nature of God. As understood by Spinoza, God is the one infinite substance who possesses an infinite number of attributes each expressing an eternal aspect of his/her nature. He believes this is so due to the definition of God being equivalent to that of substance, or that which causes itself.
Beyond this Spinoza's description of God is rather unnecessarily complex. It ends up to be something like Pantheism or Panentheism.