Please recommend a non-terrible treatment for akrasia, the unknown biological-level thing that causes me to act irrationality.
"You" are not a singular entity. Your conscious mind and unconscious mind are separate entities. The unconscious mind can do many simultaneous tasks but cannot invent new ideas. The conscious mind invents new ideas.
Your unconscious mind controls all of your actions by default. To break away from your default behavior and act creatively, your conscious mind must take temporary control of your body.
Your conscious mind can take control for only a short period of time to try out a novel behavior. During this time, your unconscious mind judges the novel behavior. If your unconscious mind likes the new behavior then your unconscious mind will continue performing the behavior indefinitely. If your unconscious mind does not like the new behavior then the new behavior will stop when your conscious mind exhausts its willpower and gets distracted.
"Willpower" equals how much your unconscious mind trusts your conscious mind. "Stong-willed" describes a person whose unconscious mind trusts its conscious mind. "Weak-willed" describes a person whose unconscious mind distrusts its conscious mind.
Remember from two paragraphs ago how your unconscious mind judges the novel behavior? If your unconscious mind decides it likes a conscious behavior then your unconscious mind does not just continue the conscious behavior. It also trusts your conscious mind a little more than it used to. (Your willpower increases.) Similarly, when your unconscious mind decides it dislikes a conscious behavior your unconscious mind distrusts your conscious mind a little more than it used to. (Your willpower decreases.)
If you want your unconscious mind to trust your conscious mind then your conscious mind must behave in ways your unconscious mind likes.
Your unconscious mind has fixed preferences. It likes good food, good sex, clean sheets, social status, kindness, beauty, revenge and sacrificing yourself to protect those you love. It is a giant bag of universal concrete contradictory heuristics.
Your conscious mind is the realm of abstract consistency. Your conscious mind wants your behavior to make sense. Your conscious mind thinks. Your conscious mind thinks it is you. Your unconscious mind is you. Your unconscious mind cannot think.
The train wreck of Western philosophy began with the "I think therefore I am."
Your conscious mind believes the world "should" be a certain way. Your conscious mind wants things. Your unconscious mind has no concept of "should" and "want". Your unconscious mind likes and dislikes things. Your unconscious mind repeats behaviors it likes.
Your conscious mind cannot convince your unconscious mind that the world "should" be a certain way because your unconscious has no concept of "should". Your conscious mind must demonstrate to your unconscious mind that your unconscious mind likes a specific behavior. There is only one way that this can happen. You must perform the behavior and your unconscious mind must like it.
…causes me to act irrationality
Your unconscious mind is in charge and always will be. Your unconscious mind has no concept of rationality. "Irrational" behavior is the default state of a human mind. Asking what "causes" you to not act rationally is like asking what "causes" the dirt in my garden to not spontaneously self-organize into an attractive girlfriend for me. It just doesn't.
Akrasia describes when your unconscious mind distrusts your conscious mind. Willpower is equals how much your unconscious mind trusts your conscious mind. Defusing akrasia equals cultivating willpower.
Growing up equals taking responsibility for your actions. I know know men and women in their 30s and 50s who do not take responsibility for their actions. I also know teenagers who did this at the age of 15 and earlier.
It is not obvious why responsibility and willpower are connected, but they are.
The best way to build willpower is to commit yourself to a situation where success and failure will be determined by your willpower and where failure will hurt your unconscious more than success.
Good examples are the United States Army Ranger School and Navy SEALs' Hell Week. Persevering through Hell Week increases your willpower because your unconscious mind learns to trust your conscious mind. If you quit Hell Week part of the way through it will also increase your willpower because your unconscious will regret for the rest of your life your decision to quit.
You can create these kinds of experiences for yourself without joining the military.
The ultimate test of willpower is pain tolerance. You are a male. For males, the most straightforward way to build willpower is to live in a society with savage coming-of-age rituals.
Instead, you live in a society where an "employee" with a "boss" living in a nation state that monopolizes the use of force is considered an "adult". Traditional Bedouin culture would consider our way of life indistinguishable from livestock.
To get the best of both worlds, you need to live in a prosperous nation state and then create your own savage coming-of-age rituals. Here some coming-of-age rituals I created for myself.
A coming-of-age ritual need not be literally dangerous. What matters is whether it feels dangerous to your unconscious mind. There are things your unconscious mind fears worse than death. Above all, your unconscious mind dislikes failing in your responsibility to the people who rely on you: children, students, customers, employees, comrades, tribe. When an Kalenjin adolescent failed a coming-of-age ritual, he was not just dooming himself to a life of involuntary celebacy. He had failed his family and tribe.
Akrasia is the opposite of willpower. Defusing akrasia equals building willpower. Willpower comes from desperation. Willpower comes from surving desperate predicaments.
Please recommend a non-terrible treatment….
There is no such thing.
 You can learn more about Bedouin culture by reading Arabian Sands by Wilfred Thesiger. ↩