Oh boy, I feel for you. Been there, done it with DC1. What a nightmare!
I wanted to post to let you know that even if you don't manage to get her onto bottles, the world will not end and she will survive.
That is what happened with my DD (DC1). She flat-out refused the bottle, over and over and over and over again. We tried everything.
So...at just before 6mo I went back to work and handed her over to a nursery four days a week. They persisted with the bottle, she took no more than an ounce at a time and cried lots.
But we all survived. She took a big breastfeed from me in the morning and another big one at night, often in the nursery car park!
At about 9mo she caved, and took full bottles. (at 18mo we then struggled to get her to stop the bottles, but that's another story)
Most babies do "crack" but I did want to post and let you know that, if she doesn't, she won't starve. Don't forget that weaning kicks in and she can start having dairy via yogurts, cheese, etc. Make cheesy mash, cheesy sweet potato mash, cheesy everything...she will be getting her milk that way even if she won't take bottles.
Lastly, please don't let this damage your relationship with her. I really did let my anxiety about it spoil my last few weeks of maternity leave and I regret that very much.
Good luck. And well done for bf'ing this long!
P.S. FWIW my DC2 was made to take one bottle a day from week one. (I still bf him but he can switch between the two, clever boy!) So so so much easier!