Although Spinoza saw a unity of body and mind, he also believed that both were two sides of the same, but could not explain this unity.
My approach says that body and mind are not two sides of the same coin, but that consciousness is a property of the brain and it has the function of orientation, just like the heart has the function of pumping blood. That's a big difference. Nowadays, Spinoza's approach is more represented by the so-called four E's. There one sits on a naïve phenomenalism and squanders the opportunity to analyze the complex levels of regulation and their connection analytically.

Life consists of molecules and can be adequately described with them. The quantum level is not necessary for this. Imagine you drive your car into a tree. What was the cause of this, such as quantum fluctuations? Of course not. You drove too fast. Quantum processes are the result of this macroscopic event. Reversing the chain of causality makes no sense.

I think life can be explained by the way (dead) molecules work together. That is, the lower level of life is molecules. Consciousness at the level of molecules can also be adequately explained with this. The fact that molecules consist of atoms and that these can be represented quantum mechanically is irrelevant. I only explain the function of a car by its components such as cylinder, fuel pump, etc.
I see consciousness as a property of the brain as the heartbeat is a property of the heart. It can be described objectively as a structure and subjectively it follows the sensitivity that is already known from unicellular organisms and occurs there as a reaction to chemical gradients.