You've constructed a strawman of the field of psychiatry and are arguing against it. I assume you mean the DSM5? It's basically a dictionary. Is the entirety of the English language and all things that happen in it represented by the Oxford English Dictionary? Read it and you've already read Shakespeare AND Google's transformers white paper!
You're ignoring mountains of studies with empirical evidence for the efficacy of various psychiatric treatments.
You think you're being empirical because you can't find a chain between a molecular chemical reaction and a given psychiatric disorder and its treatment, like the link between what a bacterial infection does to the body and then what the antibiotics do to the bacteria. I encounter this a lot in engineers, who are used to working in relatively simple, deterministic systems. If you want to blow your mind, go look up the data storage capacity of the DNA in a skin cell. Have trouble parsing a vibe coded PR, try parsing the human genome.
You're mistaken that what you perceive as subjective is related only to the field of psychiatry. The human body is too complicated to model accurately, so for example nutrition is also a highly "subjective" field leaning heavily on empirical data gleaned through studies, rather than a deterministic perfect link between the mechanisms of a tummy ache and the chemical composition of the food that might be causing it (actually it might be the food triggering a reaction in the gut bacteria which is... OR it could be psychosomatic OR it could be unrelated to nutrition at all and be ...)
If you need determinism and full system explanations to understand things, that's great, you chose the right field: computer science is easy to map. Down to the last bit, down to the logic gates in the CPU, you can describe everything, you can determine the exact cause of a bug or behavior. Biology and medicine aren't like that, especially not psychiatry. The human brain is widely considered the most complicated thing in the universe (that we're aware of). It can't be modeled or simulated with the degree of accuracy of a CPU. It's nondeterministic and unpredictable. The best we can do is do large aggregate studies and start picking apart the patterns and labeling them. It's definitely still an early science but that doesn't invalidate the treatments which studies show do work.
It's definitely weird the "power" of the human brain on human biology, but the evidence is overwhelming. Studies on psychosomatic symptoms, studies on placebo, studies on therapy treatments, if the effects weren't real, they wouldn't show up so consistently in populations across the world.
So again, I get it, you don't fully comprehend the field so you dismiss it. However I again remind you: your dismissals aren't convincing, they just expose your ignorance of this topic. Go on believing whatever you want, but I guess I'd recommend keeping this confident ignorance to yourself.
What I suspect is you specifically believe some subset of psychological disorders are "fake," am I right? If I had to guess, for people with your opinion, it's usually, depression, ADHD, maybe autism, and maybe gender dysphoria? Lots of other disorders listed. Surely you don't think schizophrenia is fake? Tourettes? PTSD? If you're gonna say the whole book is fake you have a lot of studies you need to dismantle.