Even at a coarse level there are hundreds of identified structures in the brain and hundreds of identified neurotransmitters like dopamine. Each neurotransmitter may act to produce different effects for each part of the brain.

No one will ever "fully understand" dopamine.

Almost all medications will have some side effects that patients and doctors have to balance against benefits. Good psych doctors know that everyone is an individual and even for the same individual treatments sometimes need to change.

I think your "dopamine dependency" concerns are greatly overblown.