I am yet to see a single study that supports the utility of psychodelics in the treatment of bpd or cptsd.
When it comes to my claims: DBT is to go-to modality for treatment of BPD, especially regarding symptom management. For example in: Dialectical behavior therapy: Current status, Chapman and Robins did a cross sectional analysis of recovery modalities and concluded that DBT works. Almost 50 percent of people who go to extensive therapy in that modality recover in a way of not meeting diagnostic criteria. Furthermore in Journals of Personality Disorders, a peer reviewed journal on treatment modalities, similar if not higher results are given for transference based modalities, like schema, psychodynamic, and transference focused therapy (TFT).
In Attainment of recovery from borderline personality disorder and stability of recovery: A 10-year prospective follow-up study. The longest time scale study of prospects on healing from trauma based psychological problems, slightly lower stats are given for DBT, but higher for psychodynamic and TFC.
A lot of data is available for CBT, but that is not my area of expertise, so a suggested reading is Cognitive-behavioral treatment of borderline personality disorder by Linehan. Stats are given for symptom management recovery.
Psychodynamic treatments are extremely effective around the time object relations theory was adopted for treatment of trauma based personality disorders by Kernberg. Read Borderline Conditions and Pathological Narcissism. It was early work, but shows clinically how they work and gives stats that psychodynamic treatment is fully effective granted extensive, several years worth of therapy.
In American Journal of Psychiatry, 165(5), there is a study on mentalization modalities, which are transference based, that had the length of 6 year follow up with latients who finished the coursd of treatment. Most fully recovered, the number is around 80 percet.
In Archives of General Psychiatry there is Randomized trial of schema-focused therapy vs. transference-focused psychotherapy. Claiming a win for transferencd based ones in treatment of cluster B and trauma based personality structures, although open to interpretation. Regardless, both had full recovery for majority of outpatient cohort.
As for a counter point in British Journal of Psychiatry there is the often quoted study: Pharmacotherapy for borderline personality disorder, which suggests that pharmacotherapy is not recommended in treatment of these disorders.
And this is just from the top of my head.
I recommend scientific literature for insight why it works and on current stats. Mentioned journals are a goldmine. I can give you some suggestions as to books, but these are academic books - and quite expensive.
Now kindly show me how you can doubt the validity of psychodynamic treatment of trauma based personality structures? Of which CPTSD certainly is.