Chiropractic care is one of the best things you can do. If you can specifically find a chiro that is specialized in "Websters Technique" that would be a super bonus.
If you are okay with needles, i would highly recommend acupuncture too.
I would not recommend sitting and bouncing on a ball until you get the baby anterior (baby is currently posterior if back to back). The reason why i say this is because it will help encourage the baby to engage deeper into the pelvis and that isn't something you want if the baby is face up bc it only gets harder to get the baby to turn.
Try to get the baby to turn doing thing like swimming on your belly, hand/knees (the ball is a good choice for that). Laying with your face on the bed and butt up in the air. You can do figure 8s in that position. THEN once you know the baby is anterior, the ball is excellent bc it can encourage the baby to engage in the proper position, that way baby doesn't turn back to back again.
and check this website out:
https://www.spinningbabies.com/
If you want a birth story on birthing a posterior, let me know. Thats what i had happen with my first. I can link you with it if you decide you want it.