I still don’t really understand what’s going on. This all seems very dramatic for a type of cancer that can be left for three months and potentially treated with an hour of exercise a day and an already in place coil

I’m sure I’m missing something though....
She even says in her YT video that Stage 1, grade 1a is nothing. It's the earliest form of grading and that her consultant said that she had normal cells and cancerous cells. She doesn't mention what type of womb cancer but guessing from the grading may be endometrial womb cancer. Easier to treat. She has zero symptoms, most have vaginal bleeding or irregular smears, so she's super early.
Risks for it include hormonal issues and obesity. If she works to reduce that risk factor and looks after her health then maybe in 3 months things will improve so treatment is only cell removal. However, the way she is eating, it will only worsen the hormonal issues through poor nutrition that lead to it worsening.
I'd be more inspired if she was posting about sticking to a good diet, how she's getting on with the 1 hour everyday exercise plan she was told to do while in isolation, that sort of thing. Instead, we're getting wishlists, food binges and 'wallowing' so clearly not the exercise she was told to do.