Man, you are braver than me. I wouldn't want to be on her until I settled 2 issues:
1) is this hormonal--has your Vet checked her out?
2) she submits to your authority on the ground in EVERY WAY.
You aren't "speaking horse" when you ride out the bucks, stay on during the shying and hold on during the rearing and the bolting. She really is very dangerous. IF you really like her--I personally don't like horses that behave like this
--you need to start her over, as if she is totally green. Even if you think it's not necessary she needs to learn to submit and win all of the little battles that we do when we break in a horse.
My original herd leader, "Tyke", won every battle with every horse he encountered. Often he would meet a new horse, Tyke would posture, then take a step forward, the other horse would step backwards--battle won.
Other times, he would deal with disrespect by cornering another horse, turning and kicking the heck out of the other horse. There were no other arguments after that. You aren't strong enough to fight a battle like that, but that's the battle that she is now bringing to you.
You CAN ask for perfect manners when you lead her, groom her, pick out her feet, then pull each foot forward and you decide when the foot goes down. I would also teach her to loose lunge and lunge on the line, then to long line her. She doesn't see you as an authority and doesn't trust you. She wants a SAFE authority--I personally think she is afraid of being ridden bc of some past experiences. It's going to take maybe the winter to turn her around. I would NOT ride this horse until you do so.
Tyke, 1987, who ANYBODY could handle and ride