I am always skeptical towards such theories. I think it's a simplification of the complexity of the human organism and its dynamics. I already started reading that book and was taking side notes some few weeks ago (I must already have downloaded it through your former recommendations).

Basically it involves reducing the electrical charge of past traumatic experiences.
The theory is that when one is traumatized an electrical charge is stored in memory ...

There is even talk of eliminating it. I don't think anything is "stored" as memory, it's more a memory mystery of all the dynamics involved in the body, which, according to Sheldrake's morphogenesis, for example, doesn't take up any actual space in the body itself. Rather, it corresponds to the phenomenon of communication that goes beyond one's own body, because my body and all other bodies also communicate with each other. And memory is nothing that can be stored in the sense of a materially manifested memory location. He has investigated some phenomena coming from the animal kingdom. I tend more towards his theory than that of Theta/Mest. Since I did not understand it all fully, I remain being skeptical. LOL

that later acts on one to influence behaviors, often to the negative.

Only, if you state that this kind of reactive mind is inferior to the analytical mind, while I would state that it's an interplay of the two. It's widely spread that people "mostly react impulsively" and that this is "bad". I would not make a bet that this is so. It is a matter of relation, I would say. Not sure about it, of course.

In the book it says:

One would agree that one would be healthier and happier if all the physical pain and painful emotions of a lifetime were eradicated from one's life. Dianetic processing does just that. Dianetic processing is very simple in its elements.

(I retranslated it as I just copied the formerly from English to German translation, so the citation could not totally match the original text).

Here are my side notes:

If one understands engrams as something that is connected with a sensory event, by which, apart from feeling the body, smells and tastes are also meant, which is the case here, then one would also have to erase the smell memory at the same time, which is connected with a stress-triggering event. But that is not possible.

If I once know what freshly brewed coffee smells like and I am attacked from behind while making coffee, then nothing in the world will be able to eliminate my recognition of the smell of coffee. Especially since the experience of making coffee a thousand times without being attacked is also a manifestation in the form of peaceful habit.

If I have once learnt to ride a bicycle and I then fall unhappily and heavily, cycling is not per se something that evokes the pain memory, since cycling also brings about positive sensations and memories at the same time (happy feeling of speed, physical strength, etc.). Only someone who avoids cycling after a fall is performing an irrational act, as avoidance is not a good strategy.

People have car accidents and get back into the vehicle. So they should be stressed all the time when they drive. And yet I can say that even though I have seen accidents and been involved in a few, I continued to drive normally afterwards and have made countless car journeys where I was on "autopilot", i.e. I drove and then arrived, but I was so preoccupied with my thoughts that I had basically missed the journey and was making the moves and observations that I necessarily have to make when driving, but not paying conscious attention to them.

If it were the case that a traumatic experience, such as childbearing, reactivated a woman's instinctive and inferior unconscious, she would not want to have further children after giving birth.

Traumas, for example, were consciously created among tribal peoples in order to raise boys and girls to the status of adults and to give them particularly painful and frightening experiences. This is what distinguishes humans from animals, because they are conscious actions, such trials can be planned.

If one were to eliminate the pain memories, nothing would be gained, one would have to go back to the beginning, so to speak.