I understand that you’ve been in therapy for years. You say that the therapy has not helped you. After years of therapy you should feel some relief and if you don’t, then you may want to consider a new therapist.
I do not believe that having your testicles removed would solve your problem. Your mother physically harmed you but that physical harm caused you significant psychological damage. Removing your testicles would not resolve the psychological damage. Therefore I believe it would be unnecessary and destructive to your wellbeing.
If you had them removed and continued to suffer psychologically you may be devastated that you sacrificed that part of yourself and the problem remained. I would recommend a continued focus on healing the psychological wounds; this is where the real work needs to be done.
You must be suffering tremendously if you have considered and attempted castration as a cure. You have been seriously harmed by your mother but it is important to recognize that you’re no longer a helpless child. Your mother no longer has the power to harm you. You’re an adult male who can protect himself against his mother. You have that power. It is important you understand that fact.
I hope you will continue your therapy and switch to a new therapist if you have not had significant improvement. I understand that your life experience has been agony and therapy doesn’t seem to be working but don’t give up. The right therapist can make all the difference and you can overcome the damage that has been done. Therapy for serious issues can take years. It will take time and it may not be an easy process but your life can improve. I wish you well. Thank you for your question.