Where are you? Are you near a major university teachng hospital with a Liver Transplant Center?
I was sent to Mayo by my local transplant team because of my 'rare' liver disease Primary Sclerosing Cholangitis (PSC) that was researched at Mayo. My local doctors took care of all the arrangements to get an appointment for me. I am aware that with PSC, my disease could return amd infect my transplanted liver. I wonder if something like this is happening to you that your doctors are not familiar with.
I definitely encourage you to get a second opinion about this 'rare' condition so that it can be diagnosed and that a treatment/management hopefully will be administered. Your doctor should be able to help you to get the medical records together and make a referral. You might even qualify for a research study. Does that sound like something you would consider? Do you have contact with your transplant caregiver or a parent who can help you with this?

If you are interested in contacting Mayo Clinic, Here is information to the Liver transplant Department and Contact information:
https://www.mayoclinic.org/departments-centers/liver-transplant/home
Please let me know if this is something that you want to pursue. Please keep me up-to-date on your health.