CTX at 476 within the context of your bone density and six years of no meds, I'd guess that you have luck . If you were starting the sometimes slow process of vertebral fracture your CTX would be higher. Thats provided that you had an early morning, fasting blood draw.
It is wonderful that you ordered your own test. A P1NP at the same draw would give us more information to guess your status. Testing 2 months into medication treatment would give you an idea if the meds were working.
At -4.0 my advice would be to begin Tymlos as soon as you can. If there aren't other reasons opposing HRT, I'd advise a low dose estrodial patch. Having already seen the endocrinologist, you should be able to make a request for the prescription by phone or message (today). Meanwhile be careful not to fall, don't do heavy lifting and avoid exercises that twist the spine. Be gentle with yourself as if you were fragile.
You should question advice from anyone. I don't see a choice here. But I'm not any expert.
The process for Tymlos or Forteo insurance approval can take a bit of time. Ask your endocrinologist for a free sample pen. And ask that she expedite the process.
And keep us posted remembering that we respect any choice that you make without judgement. Bless your bones.

Hey, there, late to this conversation and wondering why you are hesitant to take Prolia? My sister had her first injection a couple of months ago and has been fine. I am hoping to finish my Forteo this year and Prolia was the recommended next step by 3 different doctors I met with, including the Chief of Osteoporosis and Metabolic Bone at the Hosp for Special Surgeries in NYC. He told me to begin Prolia once my Dexa shows -2.0, and get myself to 0 after which he recommends Reclast four months after the last Prolia injection, then 8 months later, another Reclast, and then another one 12 months later and then just monitor. Or, stay on Prolia for the rest of my life.
Honestly, I have heard horror stories about every single one of these meds but after the surprise of two fractured vertebrae (from a severe Covid cough 2 years ago) and shock of discovering I have osteo, I figure its better to do what I can. Forteo makes me tired and draggy, caused belly fat and weight gain and I've been on it now for 17 months and can't wait for it to be over.
Curious about your Prolia warning. Like you, I've been active, fit, etc although I'm still recovering from what began as a shin splint then turned into 10 months of marrow edema in my tibia --from 'overuse', they say. I'm not a tri-athlete, just a now 63 year old who has always been active. Sitting like a potted plant these last few months was a test of my sanity, but, I'm happy to say I graduated back to a boot today and just took a walk around the block...slowly. Anyway, thanks for listening to my woeful tale 🙂 and if you have no fractures, I'd be torn on taking anything but supplements myself. And walking, walking, walking every day.
best of luck!

Stay off the meds. Work on building bone density naturally. Eat 6 prunes every day to help slow down bone loss. Get at least 30 grams of protein at every meal.
Make sure your taking collagen peptides every single day.