I wonder if conventional current flow is an electric field.
Conventional current flow is not physical. It literally is nothing but a math trick. It's how electronics engineers understand and analyze circuits. It is based on an old, invalid understanding of what electricity is, but it still works in the context in which engineers use it.
Back when electricity was first studied, nobody knew about electrons. They knew that something flowed, and they called it "charge." An excess of charge was called "+", and a deficit of charge was called "-", and when a conductive path was established, the "flow" of charge from + to - was called "current."
Today we know that a + charge actually is a deficit of electrons, and a - charge is an excess of electrons, and we know that when electrons are the charge carriers, they move in the opposite direction of current flow. But literally, nobody ever bothered to change the old books. We still use the old definitions of "charge" and "current" because the old math still works.