At the absolute minimum she must have been diagnosed with complex hyperplasia with atypical cells to warrant the hysterectomy. In layman's terms thats a very thick endometrial lining where the cell changes are already showing pre-cancerous cells. My gyn/oncologist when running through the stages etc said "make no mistake that's still cancer" even though it's pretty much considered stage 0. If that was the case though I don't believe they would have operated on her due to her size, as at this stage they tend to just use progesterone to hold the cells at bay until the patient loses enough weight to safely operate, which is how Life by Jen was being treated (also Amanda from season 2 of Family by the Ton). Amber's situation was clearly deemed necessitating the hysterectomy but they mitigated the anesthesia risk by using an epidural block rather than giving her general anesthesia....that's not commonplace, but the little she has detailed about that surgery and her recovery ring true that a spinal block of some kind was used. I don't remember exactly what Amber's paperwork said but she was either late stage one or early stage two. At the time I thought her paperwork looked genuine. All this being said, much of the treatment etc she's spoken of since, she could very easily have gotten from internet forum groups that deal with uterine cancer. The information available on sites like hystersisters is incredibly detailed and nearly always very consistent, so she could potentially bluff her way through conversations after reading up on the processes. I'm surprised shes using terms like "cancer free" and "her Dr agrees". I've just passed the 6 year mark since my surgery, and certainly not been told that by my specialists although after 5 years they tend to not follow you anymore. I suspect she might well be trying to convince herself that the cancer is gone simply so she can blow off her gyn/onc appointments, because guaranteed she's not happy having an internal pelvic examination every 3-6 months...and yes they still shove that speculum up there for a look around even with no cervix, uterus or ovaries.
Edit to add: They also would not have taken her fallopian tubes and ovaries at her age if she didn't have cancer. Thanks
@Turd Fergusson for confirming she did indeed have a TAH BSO. I'm really stumped by why she was prescribed estrogen when she had an estrogenic cancer.